Ask HN: Buying a startup?

I've been reading about startups on HN for awhile and getting ready to dip my toes into the water! I'm likely putting an offer on a small e-commerce site with some friends in the following days. The site is incorporated in NJ. My partners and I are in CA, MA, and NJ. Is there anything I should consider from a legal aspect? Do we buy the LLC or all the assets (domain name, etc.)? What should we do ourselves vs. with a lawyer? It's a small site, so I don't want legal fees to be too large a percentage of the total transaction.