The Bills Store has a discount on James Cook's jersey with his original number. It's a better deal than what I usually see listed for this sort of thing online. In person, you can find better deals, but for us out-of-towners, the pickings are usually slim.
Anyway, I haven't bought a new jersey in forever, but this seemed like a good time, so I grabbed one. If anyone is interested, here is the link: https://shop.buffalobills.com/collections/player_james-cook/products/nike-game-home-james-cook-jersey