Those are pretty good numbers Pat! I have seen the ads like what Babs has quoted. I know I've never come close to that!
Mostly, I do it for the satisfaction of it-nothing like walking out to your garden and picking a tomato for your sandwich. Or picking a melon ripe from the vine and eating it for breakfast. Or picking tender baby squash for dinner. There's an immense satisfaction to doing that! And it tastes so good, especially when you grew it yourself!
We eat a lot of produce (vegetarians and fruit/veggie lovers here!). I'd love to actually grow enough to can/preserve but so far, I haven't had a productive enough garden for that. Hoping this is the year! We've invested more this year-some garden soil/compost to build up our soil and some containters too.
I do a combo of seeds and plants. Plants are definitely more expensive but I've had much better luck growing peppers and tomatoes (especially tomatoes) from plants than seed. So I buy plants for those and seeds for most everything else (squash, melons, cucumbers, herbs, lettuce, etc).
This year, I want to make our investment produce more than just enjoyment . . . I really hope to see some savings in our grocery bills! And I have tons of canning jars just waiting to be filled with homegrown salsa, pasta sauces, etc! Fingers crossed . . .