I lucked into a little 400 sf space in the back of an office building. The first bit of advice is to check with the HD and find out what the min requirements are. Then check with the city and make sure your location works for them. I opened back in March of 2010. So far about 24k sunk in the operation. Im tiny, and only do catering. Gives me the time off too from time to time. Yes you do need an accounting service but I highly suggest learning quickbooks. it can save you a lot of time and money.
This is a LOT of work but worth it. Its also a lot of fun. Working farmers market is nothing like an event. we do markets on the weekend. Makes for god advertising and has gotten us a lot of business.
Insurance and making it legit is important not just to be a good employer but also to protect yourself. You dont want to louse everything just because you got bad meat from a provider. No matter how much you watch it, it will happen some day.