You can find 5-oz packages of Hormel Cup N' Crisp at select retailers nationwide for a suggested price range of $3.49 to $3.99. It's available in original and bold varieties.
If you're curious as to what causes pepperoni to cup as it's heated, Serious Eats has a fairly thorough article on the matter that basically concludes, "For the cup-iest pepperoni, get natural casing, and slice it medium-thick."
Photo via Hormel.