I have a 64 sq ft raised bed. I don't remember how much the materials cost, but it was over $100 for sure.
In it I grow bell peppers, cucumbers, eggplant, and spinach. I also grow tomatoes on my front porch, and have 4 blueberry bushes.
I get enough peppers for a summers worth of grilling and salads, a few dozen eggplant, and I get a couple of salads out of the spinach each week(though last year was bad for spinach for me). I get more cucumbers than I could ever eat and end up giving some away and pickling a bunch (delicious and easy). I eat a handful of blueberries a day just right of the bush and full a bowl weekly to bring inside. I also get well over 100 cherry tomatoes, probably a few hundred but I've never counted.
I don't do it for the cost savings, though I've certainly saved hundreds of dollars. I do it because it's nice to just be able to walk out to the garden and grab something for dinner.