Ask HN: Tips for evaluating a startup offer.

I have an offer to join a startup as a first hire and am trying to figure out if it is worth doing. There are two founders, one of which is putting his own money up to bootstrap with. In the first year, one founder will commit between 150k to 210k in cash, the other will work with no salary. Both founders are absolutely key to the idea working as they have the industry experience, smarts and contacts to get going with. They are looking at hiring two to three people, one of them being me. The offer that is on the table is this:  Option a) take a salary at 40% market rate in year one and receive 3% equity. Option b) take no salary in year one and receive 6% equity. With both options, if we live into the second year, my salary would go to 80% of market value. If we live to year three, market value salary is restored. The exit that is being targeted is in the 30 to 50 million range. The company is not planning on taking VC with the founders sorting out more funding through personal finances and a little revenue in year two. The idea is solid. The problem is really interesting. We are all new to the startup world which is why I am a little worried about the offer on the table. We haven't started hacking yet so there is a load of risk around building the product and interest in it. I would be very grateful to hear what you think about the options on the table. I want to take the plunge, but only on terms that make sense.