New users who sign up using a TopCashback referral link can receive a $25 sign-up bonus or UK £ equivalent, often £10. To qualify, new users must sign up, verify their email, and earn at least $10 in payable cashback from their purchases. Existing TopCashback members can earn a $35 referral bonus for each friend they refer, though this can vary. When your referred friend signs up and earns at least $10 in payable cashback, you will receive your bonus.