I'm a farmer's market vendor, I just got in from there. I think inspected kitchen rental rates probably vary greatly location to location. Around here, there are quite a few inspected church kitchens. Maybe you could do a search on that. You need to do some research also on the regulations on things like keeping warm food warm (what temperature are you required to maintain) and whether or not handwashing facilities at your booth are a requirement.
I'm not sure if you'd consider selling baked goods or candy but in my state it's permissible to sell them from your home kitchen as long as you mark it 'not for resale - processed and prepared in an kitchen without state inspection'.
Find out who your food safety specialist is in your local dept. of agriculture and consumer services and give them a call. They should be able to give you lots of info and assistance. Good luck!