Are we talking fresh tomatoes, canned, dried? Sauces? Peas--English or snow pea? again perserved or fresh only?
If canning tomatoes, I figure about 30 plants (usually can't stop and end up with many more), plant a few snow peas (about 20' row) but that is for fresh only (2 of us). My garden is 30' X 50' with another sweet corn patch of 30' X 30'. When garden is producing, I have plenty to share with friends plus what we eat. It supplements our food bill in summer, little in winter but by no means do we live off it.
If you were going to grow enough for family of 4 to eat off of all year long (tomatoes, potatoes, sweet corn, etc), I'd guess close to 1/2 an acre.