Have you tasted store bought vegetables? Farmers market may be grown, may be store bought. I have 2 4x2ft planters full of veggies, out $200 this year setting it up. Next year just the price of seeds.
Seeds and amendments. You gotta add more nutrients to the soil or else your yields will start to suffer. Although, there's a lot of permaculture ways to add nutrients for free.
Unless you live somewhere with 0 soil quality or literally never do any work to fertilize it's not that much extra cost to fertilize and keep soil doing well
Run a compost heap and you're practically going to supply yourself with everything needed for free if you can scale it enough (which is like, 2 2x4 beds and remembering to dump organic food remnants too)
Oh for sure. You don't need much. I just recently watched a cool video about tossing all your weeds in a couple of small water barrels to make liquid fertilizer. It doesn't take a lot.
We grow the vast majority of our own veggies, eggs and chicken. Our kids hate store bought food, it's even hard to go to restaurants. We sell a little bit from an on site farm stand to help pay for supplies mostly. Our seeds were $600 this year though. It's a rather large and diverse garden.