Coupon
/ˈkuːpɑːn,ˈkjuːpɑːn/
noun
A small piece of paper that gives you a discount or the right to buy something.
She clipped out a coupon for 20% off at the furniture store.
Often appears as...
discount coupon
shopping coupon
Definition 1 of 4
Pro Tip 1/3Save Money
Coupons often give discounts on items you would buy anyway, helping you save money. 
Before buying groceries, I always check for coupons to cut costs.
Pro Tip 2/3Time Sensitive
Coupons typically have expiration dates; use them before they lose value. 
This coupon expires tomorrow, so I need to use it today.
Pro Tip 3/3Promotional Tool
Companies use coupons for promotion, which means they might require additional spending. 
The coupon gave me 10% off, but only if I spent over $50.