cash-back
US /ˈkæʃ.bæk/
UK /ˈkæʃ.bæk/

1.
a system in which customers are given a small amount of money back when they pay for something with a debit card or credit card, or when they make a purchase at a store
:
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I got some cash-back at the grocery store.
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Many credit cards offer cash-back rewards.
1.
relating to a system where money is returned to a customer
:
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This credit card has a great cash-back program.
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They offer a cash-back bonus for new sign-ups.