First market date, your zone and what will you have to sell?
Our market starts May 7th. Ours is a city run market and some of don't like the hours, others do. It's Tuesdays and Fridays 10-2. Not a good time if working during the day like lots fo people do, but it's a newer market (3rd year) and things are still getting worked out.
I'm Zone 6 and will have lettuces, kale, onions, herbs, vegetable plants/seedlings, radishes, and strawberries.