I usually use a big can of tomato sauce, unsalted, a can or two of tomato paste. Hit the spice rack and add Italian seasonings, garlic powder, basil, oregano, a little onion powder,  and most important, some Parmesan cheese. (I like a smooth gravy, not a chunky sauce)

Never really measure anything, just put in what I think is the right amount, usually in the area of a teaspoon or two.