Clubs swindle that puts extra on bill (5,6)
I believe the answer is:
cover charge
'that puts extra on bill' is the definition.
(fee added to a bill)
'clubs swindle' is the wordplay.
'clubs' becomes 'c' (abbreviation in card games).
'swindle' becomes 'overcharge' (to overcharge someone is to con or swindle them).
'c'+'overcharge'='COVER CHARGE'
(Other definitions for cover charge that I've seen before include "It's made by a restaurant" , "entrance fee?" .)