Coupons can be redeemed at the place where you see coupons in CF. The best prize is "Gold AK-47", but you need 180 #- a Grenade bag needs at least 15. This is a way for Tencent to attract lottery, which is not cost-effective. 300CF and 500CF are almost lottery tickets, so don't draw a lottery. You'd better draw 800CF dots. It's a good deal.