Decent electric grinders are pretty cheap, and worth it, I’d say.
But pre-ground coffee is much easier to find than beans, you just need to make sure you get the right grind for your preferences. In an Aeropress, if it’s an Espresso grind, don’t brew it for more than ~30 seconds (with a bit of a stir). If it’s a coarser grind, use the inverted method and brew it for 2-3 minutes before pressing. You’ll need to experiment a bit to find out how you like it.
You can get permanent metal filters for the Aeropress. Connoisseurs will tell you it makes a difference, I just want minimum hassle and running out of filters is a hassle.