Show HN: I made a site that calculates the market price of items on ebay

http://www.getmarketprice.com/

by locksley • 13 years ago

87 61 13 years ago

locksley24• 13 years ago

This was my weekend project. I made it after being frustrated at not knowing what a fair price for an iphone 5 would be on eBay. I posted this a month ago but wasn't ready for HN traffic. Learnt about load testing the hard way and have optimized it since. So, here it is again.

Feel free delve into any questions.

brador• 13 years ago

What did you learn about load testing and optimisation? Any tips, cribnotes?

locksley24• 13 years ago

The most useful tip I could give you (if you're building on rails and deploying to heroku) is to use a Unicorn Webserver. It allows your to handle far more concurrent requests.

This article explains it better than I ever will.

http://blog.codeship.io/2012/05/06/Unicorn-on-Heroku.html

I'm running 8 unicorn workers per dyno at the moment and that's still within the 512mb memory limit because I'm not using ActiveRecord.

espadagroup• 13 years ago

Why not try priceonomics they're pretty good for that. With that said nice app!

drd• 13 years ago

They are using different sources. This site is using eBay information. Priceonomics is using classified ads, I guess mostly from Craigslist. Actually, the user can benefit from both by comparing the results on two different market-places.

Locksley, keep up the good work. You need to clean up the results. Removing the unrelated items is desirable. This has a good monetizing potential.

slashdotdash2• 13 years ago

Neat site, thanks for sharing. Here's some constructive feedback for you.

* Filter results by eBay category.

* Outlier elimination such as excluding "broken" items (e.g. listings containing commonly used words such as "spares or repair", "cracked screen", "damaged").

* Country specific currency (e.g. for UK searches show the results in GBP, £).

* Predict a fair market value for a given search. Useful when trying to sell items second hand as an "arm's-length transaction".

jherrick• 13 years ago

Good list. I would also suggested eliminating outlying items based on prices. It seems like when there are dozens of items named XXX, there will be several with "hard drive for XXX" or something.

I must believe there's any easy way to eliminate some "outliers" using mathematics, but I can't recall the function(s) to do so.

locksley24• 13 years ago

Thanks for the feedback! Really appreciate it

jcampbell1• 13 years ago

Are you familiar with TerraPeak? It is a company that provides access to all completed ebay sales. It is a SaaS product and sells for like $20-$50/month. I gather their annual revenues are around $15M/year.

Just pointing out that there is a decent sized market for this type of data.

locksley24• 13 years ago

Wow, had no idea they could be making so much. I've come across their "Research API" before but didn't think too much about it. Will have a look into it now. Thanks man

nos4A2• 13 years ago

Looks awesome! Some outlier elimination would be great (on a search for a graphics card there was skew due to unrelated items)

locksley24• 13 years ago

Hey thanks! I'm just using a filter of 2 standard deviations within the median at the moment. Any ideas on how to do it more effectively?

xabi• 13 years ago

Nice site! Could you please add more countries? Spain (ebay.es)?

h2s• 13 years ago

Bug report: choosing US, UK or AUS from the country select dropdown causes the form to submit as if you'd typed in the country code as your search term.

This is a really killer piece of kit though. I'm very impressed. It's something I think many of us have idly imagined when struggling to determine a good starting price for a new eBay auction.

locksley24• 13 years ago

Ah Crap, thanks for letting me know. I'll patch it up tomorrow, it's 12:30am here in Melbourne!

GotAnyMegadeth• 13 years ago

Suggestion: You should be able to exclude certain data items from the calculation, then recalculate (check box for exclude next to the raw data item or something). I just did a search for "fender aerodyne bass guitar" and the lowest price that came up was $249.99, though that turned out to be only the neck of a bass "2007 Fender Aerodyne JAZZ BASS NECK Tuners Bass Guitar Black Headstock".

locksley24• 13 years ago

That's a good idea. I'm planning to build a pricing filter slider on the results page because it seems most people have a rough idea how much an item is worth.

Your problem was the reason why I filtered out results below $100. There's just too much junk below that range like "Fender Bass HELLO KITTY STRAP". Eventually I'll have to think of a way to algorithmically exclude those results.

Thanks for the suggestion.

makethetick• 13 years ago

Looks great and could be a very handy tool but I would of expected prices to show up in £ rather than $ when selecting UK.

locksley24• 13 years ago

Thanks for the pick up.

joshcrowder• 13 years ago

This is great, very impressive. When searching for an item in the UK the price still shows in dollars.

styluss• 13 years ago

What's your stack?

locksley24• 13 years ago

Rails (without ActiveRecord/Database) Heroku Unicorn Server

nawitus• 13 years ago

Nice site, but I would like a third graph which shows (e.g.) the average price (for the day) in the y-axis and days in x-axis, so you can estimate how the price has developed over the last few weeks.

locksley24• 13 years ago

Yeah this would be interesting and I can certainly do it for popular searches.

To do it for all items would require collection of lots of data in my own database though. Will have a think about this.

frantissek• 13 years ago

Hey, I like it so. If want to design-up that site, let me know. Fkrivda.com

jbrooksuk• 13 years ago

Clever idea, it's always time consuming to explain to my father in law that he'd be better off buying something new in the shop or online.

locksley24• 13 years ago

Thanks! Similarly, I've convinced my grandma to use this.

EvaK_de• 13 years ago

Ah, that comes very handy! Thanks.

Would it be possible to show the full link when hovering over a truncated link ("lin...")?

locksley24• 13 years ago

I guess this would be simple enough. From what I know, it'd just be adding a title attribute with the full text in the anchor tag.

xanmas• 13 years ago

I tried to search for a speedmaster 3510.50 and it cut off everything after the period. Regex issue?

momop• 13 years ago

Nicely done and Good luck!

lilfeetpete• 13 years ago

Great job, in addition to the comments already made I think it would be more useful if it said what you would make from a sale after ebay and paypal take their cut from the sale.

slashdotdash2• 13 years ago

Agreed, that's a great suggestion. It's always surprising just how much of a cut the eBay & PayPal fees take away from the final sale price.

locksley24• 13 years ago

That's a good point. Ebay takes around 9% and Paypal around 3%. After postage, it'll cost you around 15% of sale.

ericcholis• 13 years ago

Small bug, searching for "2012/13 Panini Elite Basketball Hobby Box" confuses your URL pattern, only searching for "2012"

locksley24• 13 years ago

Ah balls. I'm on it.

radiospiel• 13 years ago

Just curious: this is not in line w/ebay's T&C, or is it? Quite impressive, anyways.

fishpi• 13 years ago

When I looked at doing the same thing a few years ago, I found it was explicitly ruled out in the conditions attached to the eBay API. There may be a way to get by under the radar, but I considered it a sufficiently sketchy business model I abandoned the idea.

ahmadss• 13 years ago

if you're not using ebay's api, then how are you gathering this data? or am i reading this incorrectly and you are indeed using ebays api?

regularfry• 13 years ago

The search term "win&win riser" breaks it. Looks like you're not url-escaping the search term?

EDIT - also it looks like you're submitting it to ebay badly, the results for "win&win" are same as for "win".

locksley24• 13 years ago

Ahh, thanks for the heads up. I'm using a URI Escape function on the search terms and that might be breaking something. Looking into it now.

nekgrim2• 13 years ago

And you're on lifehacker : http://lifehacker.com/5986983/market-price-calculates-what-y...

Congratulations!

nekgrim2• 13 years ago

and on The Next Web : http://thenextweb.com/shareables/2013/02/26/this-site-tells-...

locksley24• 13 years ago

This was crazy, thanks for letting me know!

My servers surprisingly seemed to handle it ok with one minor crash.

tharshan09• 13 years ago

This is a really nice little app. I mean I have only used ebay only a couple of times but this is really nice, and its something I kinda wish I had at the back of my mind when using ebay.

Can you give a little details on how it works? Is it scraped data? etc.

I know this is targeted at a person who wants to sell items on ebay, but I am a buyer and I find this still quite useful. Not sure how up to date the data is but the graphs are an amazing feature! Makes so much sense.

locksley24• 13 years ago

Thanks for the comments!

I actually originally intended this for the buyer! I wanted an iphone for myself, so I scraped the 'completed listings' page on ebay, and converted it to csv to build a histogram in excel.

The data is up to the minute. But I cache the queries in order the save computational resources. Each cache expires within 15 minutes.

Initially the data was scraped, but then I moved to the API which improved performance by 200 - 300%.

therobot24• 13 years ago

seems to break when i put in a specific season, ex:

- "dexter season 6" returns only listings where season 1-6 are sold setting an average price at ~$140 - "simpsons season 9" returns listings where multiple seasons including season 9 are sold setting the an average price at ~$150

In each case the 'raw data' had more than one season in it

locksley24• 13 years ago

Hmmm, this is difficult to fix because it relies on Ebay's search engine. The only solution I could think of is to add a 'price filter slider' on the results page. This way, you could set the limits to how much you think Dexter Season 6 should cost.

xur17• 13 years ago

Is there any way to search for a certain condition only? When I search for the iPhone for example, it returns a huge range of prices that include ones that were used and refurbished.

Otherwise, it looks like a great site!

locksley24• 13 years ago

Ebay's API might have a 'condition' property, I shall check.

In the meantime it's probably just as effective to put the condition as a query, i.e "iPhone 5 used"

booruguru2• 13 years ago

Very neat site. I think overtime, you should try to find more visually pleasing ways of presenting the data, but for now it's not a deal breaker.

I have a suggestion: Perhaps you could build some kind of e-mail alert system that lets me know when there's an e-bay "Buy Now" item available within a user specified price range. You could also let me know if there an item I want is still within a certain price range hours before the bid closes.

EDIT: Typos.

locksley24• 13 years ago

You don't like the charts?

I'm guess a stats nerd so I like to see that stuff haha.

I like your feature suggestion, just put it in my product backlog.

hobs2• 13 years ago

Do not remove the charts. I love the charts.

They are simple and obvious, the only feedback I would give is that I would think (not being a huge ebay person) the current charts might actually be changed up a bit. I would be more interested in seeing the clustering of prices, or something like how long the listing has ran without a bid (indicating more likely desperate takers and the like). If the current charts do influence the price in some way that can be used that is advantageous to the buyer, then I would rescind my comment.

Sent this site to a few friends who don't read HN, they are highly appreciative.

booruguru2• 13 years ago

Dude, put a contact link on your site so people can give feedback. Also, once someone does a search, you should pass the search query into the search box so they can make modifications without retyping the whole thing.

locksley24• 13 years ago

Yeah, that's on the product backlog! But I'm a full time law student doing this as a side project in order to learn how to code.

NEED MOAR ENGINEERS

rokahnhn• 13 years ago

Possible bug report: I searched for "thunderbolt LCD" and [recently ended graph] doesn't seem to match up with prices in [recently ended table].

locksley24• 13 years ago

Hey you sure about that? Seems to be fine for me. But there are two obvious clusters. Perhaps two different LCD models?

http://www.getmarketprice.com/results/thunderbolt-LCD/

Show HN: I made a site that calculates the market price of items on ebay

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