I just read an excellent article by Barbara Damrosch in the current AARP magazine about 'Dirt Cheap Eats' extolling the benefits of growing (some) of your own vegetables. Unfortunately, the online version doesn't have a link to her piece, or I'd provide it.Damrosch is an accomplished garden writer and gardener, and along with her spouse, Elliot Coleman, are totally inspiring with their gardening endeavors in Maine. Coleman's 'Four Season Harvest' transformed my thinking about vegetable gardening here in a mild winter area.
She suggests, quite wisely, starting small, but points out that a small plot (12 ft x 12 ft) can produce up to $500 worth of vegetables for a modest investment in soil amendments, organic fertilizer, and seeds (approximately $50), if you don't have to fence out critters (add another $150).