I can't see why you'd use cans either; real food tastes so much better. I'm doing another batch of Oven Roasted tomato sauce:

2kg ripe tomatoes (more if I have them)
2 big onions, roughly chopped (I use Spanish)
12 garlic cloves
dash olive oil
2 tbsp balsamic
1 tbsp brown sugar
salt and fresh pepper

Halve/quarter tomatoes and toss with garlic, onions and olive oil in a baking dish. Bake for an hour 200C or until tomatoes are soft and slightly scorched and onions are cooked. Cool so you can peel off and discard tomato skins (or not) and squeeze the cooked garlic over the tomatoes. Add the balsamic, sugar, salt and pepper and stir (or whiz to a mush if you prefer). Reheat and serve. Freeze whatever you don't use in meal-sized batches.