They’re buying/selling a one-time redeemable coupon. Gamedevs have learned to stop distributing those coupons for a variety of reasons. I believe that coupons

They’re buying/selling a one-time redeemable coupon. Gamedevs have learned to stop distributing those coupons for a variety of reasons. I believe that coupons should not be transferable once redeemed. Selling an unredeemed coupon is, of course, acceptable.