Beater employed at a discount? (6)
I believe the answer is:
rebate
'a discount?' is the definition.
('rebate' can be a synonym of 'discount')
'beater employed' is the wordplay.
'employed' is an anagram indicator (the same letters employed in a new way).
'beater' is an anagram of 'REBATE'.
'at' acts as a link.
(Other definitions for rebate that I've seen before include "Money back, partial refund" , "price reduction" , "Sum paid back" , "Give back (money)" , "Return of, eg, tax" .)