This will be my first year at a market, so I'm by no means an expert here, but in my wanderings at the several farmers' markets last year to do research, the people that sold seedlings did really well, $2-$4 a plant, although they didn't sell very long--probably sold out. Lots of hybrids and cherries. All in all, basically the same varities as Wally World and the like. Brandywine, Brandywine, Brandywine with some Mr. Stripey's thrown in. Since I'm concentrating mainly on the heirlooms to sell, I'm planning on using my extra seed to grow seedlings to sell, about 75 different varieties, but mainly just to use up the extra seed and to experiment with what works. So, in my inexperience, I would say go for variety, and see what sells best. I know I would have sold my soul last year if I could have found someone--anyone with something other than Brandywine after Bambi and her extended family terrorized my tomato, TOMATO seedlings and I had to go scrounging for transplants. Sidenote: Okay, Bambi and I have had this love-hate relationship for years. I know what she likes, corn...lettuce...just about everything...so I plant extra every year so she'll leave my main crops alone and in return for her respecting my boundries I don't let my husband shoot her. But she has always...ALWAYS LEFT MY TOMATOES ALONE. Except last year. Tomatoes were the only thing she touched. Gonna fix her this year, though, heh...heh...heh. Anywhoo, since I couldn't kill her last year, I would have killed to have found someone with a great selection of varieties. That was my point. Would've paid alot of money, too.

Added thought...have you given any thought to selling varieties timed to plant with peppers/basil/etc. to sell as a group? It's been mentioned on this forum several times and I would think that would be an additional way to bring in sales. Guess it would depend on the amount of room you have to work with, though.