You can grow your own for next to nothing. It's relatively expensive to get started (soil, soil amendments, seeds, etc.) but after that, you just plant, maintain, harvest & re-plant.
I've grown tomatoes, cucumbers, kentucky wonder beans, pinto beans, red beans, yellow squash, zuchinni, cantelopes, honey dew melons, watermelons and strawberries this year. I'm looking forward to a crop of citris later this year/early next year and avocados.
You have fresh veggies for perhaps one month a year.
It's not really next to nothing when you factor in the work required and the yield you get, and the small window in which you can yield and eat your crop. It's pretty much a waste of time.