With all the tomatoes we got we made a large pot of marinara and then canned it. My husband has a wonderful recipe from being a cook at an italian restaurant back in high school. What a great job for a husband to have had, huh?!?! ;) It certainly comes in handy. Back to the marinara...
We had about 15 pounds of blanched, peeled and cored tomatoes and decided to make it all. There are a lot of recipes on the internet, but like we do, you can also can a favorite family recipe. We leave meat out of ours because the canning is less complicated and less likely to have spoiling issues. Although, if that is something you'd like to do, it is possible, just be sure to look into the requirements before doing so. Another thing to keep in mind is that if you do your own recipe when canning you need to balance the acidity levels (which basically means you have to add vinegar or lemon juice to some recipes). For marinara we found that we need to add 1 Tbsp of lemon juice per jar, so we simply pour it into the jar as we pour the marinara in to make sure to get the measurements right.
I can't guarantee that this will be a cheaper then buying cans or jars at the store, a lot depends on your recipe. For us, it's probably comparable because we are okay with buying the $0.88/can kind. Although, I can guarantee that yours will be much tastier! :) To save money we buy the cheaper one, but our canned version far surpasses it in flavor and quality for about the same price or maybe even a little more. It's worth it though! :)
The end result--yummy!