Money-back deal (6)
I believe the answer is:
'money-back deal' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rebate that I've seen before include "Cash refund" , "Give back (money)" , "Refund of part of the amount paid" , "Discount - tax return?" , "Money back, partial refund" .)