I make a lot of stuff, either for quality, cost, or fun. I have berry vines in my backyard, so I make jam, which is a pain but reminds me of childhood summers with my Granny. Not sure it’s any cheaper, when you count the hardware and cheap jams available, but I do mine with no sugar, which is very hard to find (at least without some version of sugar substitute — don’t want extra sweetness, thanks, just want the fruit!).
I will also make my own mayo (with olive oil), bread, pasta, etc. when I want quality versions (even though I also buy the cheaper versions for everyday), because they just taste delicious.* And pizza dough — make a big batch in the Kitchen-Aid, divide it into individual portion sizes, and freeze. Oh, and marshmallows. I gotta say, pizza parties and marshmallow-making are two of the messiest, most fun things you can have in the kitchen with kids.
I don’t even count baked goods here — I can’t remember the last time I used a box mix for anything, when it’s so easy to throw flour and baking powder and sugar/salt together.
And sometimes I make my own just because the store has pissed me off. A few weeks ago I needed ground pork for a recipe, and the store was selling it for like $4-5/lb — right next to a whole pork loin for $1.89/lb. So I bought the pork loin, used half of it for the recipe, and still have another roast in my freezer, all for the same price I could have paid for just the ground pork.
Right now, it is all pretty much hit-or-miss, depending on my mood and available time. I suspect when I RE, I will make more on my own as I will have plenty of time to putter in the kitchen.
* Per the question above, I have a whole mess of attachments for my Kitchen-Aid, including the pasta roller/cutters, the grinder, and the shredder. So I can do pretty much anything I need without having to own multiple different specialty tools.