The cost of growing your own depends a lot on your soil and climate. I grew up in Ohio. We had good soil and plenty of both rain and sunshine, so it was much cheaper to grow your own. Now I live in Central Texas. We have very poor soil, so you pretty much have to build up the soil wherever you want to garden, which is expensive in both labor and materials. On top of that, while we have plenty of sun, the rain - <sigh> not so much. Watering a vegetable garden (while much better with the square foot gardening method), is an added expense. On the other hand, there is simply nothing so good as a home-grown tomato. Just for my own use I have 8 tomato plants (different varieties with different harvest periods).