I start with beans, garbonzo/chick peas/chana are my favorite. Sometimes I take a little of a few different kinds, and soak them overnight. You can also just use whatever you have on hand. The beans are important for protein.

Put the canned or soaked beans into a big pot, add some kind of tomato product, whatever you have. I've done this with canned tomatoes, chopped fresh, a big can of tomato juice, tomato paste, it all works, just use what you have/like. I wouldn't recommend ketchup.

Add some water, and salt and pepper to taste. Sea salt is much better for you, and is a very easy, simple and cheap diet change.

Once that's boiling, I start adding veggies. You can just add a bag or two of frozen veggies, mixed is good, but so are green beans. Potatos and carrots are good, but add those earlier as they take longer to cook than other veggies. Whatever you have from the garden is great, summer squash, even finely chopped spinach. Leftover veggies are fine.

This is real good with a nice slice of heavy brown bread and butter. You can also add dry pasta right to the boiling soup. It'll cook just fine in the soup. You can make a minestrone this way too.