What season and what time do you want your crop ready?

Oh Lolz, sorry about that. I'm looking for a crop as early in spring as I can get. FWIW, I already have garlic and shallots in other beds.

Early spring greens like spinach, kale or lettuce would be best and than when that is out in about 80 days plant green beans as they do not do well in rely spring unless you are in the south, than you could do beans easily.

One bit of advice, avoid planting crops you don't like eating because if they do not sell than you eat them so grow things you like.

You bring a good point up b/c I would not think of most greens as a farm stand traffic stopper. I'd be looking for a crop that will turn heads and then the shoppers will also buy the greens.

Think about an early tomato crop although it will require more input than you currently have. If you have long-range planning you might put out a half acre of asparagus next spring- it starts my year off on solid footing. With a high tunnel /greenhouse you can extend the season with all sorts of good produce- Tomatoes and cucumbers are prime candidates.

maybe you could do so special looking lettuce mixes with some red and light green and frizzle leaves, or freckles--and while they're growing, you could seed some rows of snap peas on trellis in between them. That would extend your time and I don't see a lot of them in the market, but I've had people ask about them lots of times.It also depends on how much hands-on work you want to do with them. You could also snip a few pea shoots for you mix.

In my experience lettuce is a very popular early crop as is spinach but the most popular of all is asparagus but you need 3 to 4 years for it to mature enough to be harvested and you need several hundred feet, minimally, to make money.