Third-Party
  Upsized cashback at Shopback. Can stack with existing 15% off goods (Code: CYBER15).
 
    Upsized cashback at Shopback. Can stack with existing 15% off goods (Code: CYBER15).
$30 for referrer, $20 for referee after referee qualifies (minimum $50 spend via ShopBack in 180 days and received at least one "Confirmed" cashback).
Qualifying requirements for referee: 1. Made a minimum $20 online purchase (below exclusions apply), 2. Received a minimum $10 confirmed cashback online, 3. Added banking details to account.
Users will need to fulfil the referral criteria within 180 days from referee's sign-up date to unlock cashback. See all terms

And Tightarse.
Cashrewards has 20%.