I have started making my own jam and now I never want to buy it at the store again. The first time, it was because we had a surplus of strawberries from our farm share. Now they are done with strawberries, so I picked up two bags frozen, plus one bag of blueberries. They are organic and were something like $2.50 each at Aldi. So far I have made three batches and learned that you want to use fruit pectin, not gelatin. So those are the main ingredients, in addition to sugar and a few flavorings.
You can eat this great stuff the next day, or freeze it. A fresh batch lasts about ten days in the fridge (it will be gone before then). If you freeze it, leave space in the jar for it to expand. This stuff is great in yogurt -- a lot less sugar than the traditional "fruit on the bottom" variety. We use it on pancakes, biscuits, muffins, sandwiches, etc.
When you look at all the sugar in jams and jelly, it makes this method very attractive. You can buy "fruit only" products, but they are expensive. I think that the cost of my home-made version is probably three bucks per pound, which is a lot more economical and healthy that store-bought. Best of all, it's so easy anyone can make it.