My stroller doesn’t come with a cup holder, which has been kind of annoying. We looked into buying one in the store, but I didn’t like the designs and I had a problem with spending $7-$15 for yet another plastic thing.
I don’t know why it never occurred to me to make my own until I saw this tutorial for a stroller cup holder. It’s a simple fabric cylinder with a flap that folds over the stroller and snaps in place. Looks like it works!