I can make ___ but I almost always buy it.
Pickles. I love all kinds of pickles, so I buy different types and brands. I could make them. I sometimes make them. But I always have store-bought ones on hand.
Jellies/jams. I use sooooo little of the stuff. If I open a jar to put it on toast, the next time I open the jar, there's fur in there. Now, I only open a jar if I'm planning on cooking or baking with it soon enough that I know I'll use the whole jar. No sense in making batches of it and then storing it forever.
Tortillas. There's a place down the street that makes them, and they're good and they're cheap. I've made them, and will probably do so again, but only when the tortillas are a star ingredient, or when I've got lots of time to kill.
That's a good start.