Boozer with drink accepts a discount (7)
I believe the answer is:
bargain
'discount' is the definition.
'boozer with drink accepts a' is the wordplay.
'boozer' becomes 'bar'.
'with' says to put letters next to each other.
'drink' becomes 'gin' (gin is a kind of drink**).
'accepts' indicates putting letters inside.
'gin' going around 'a' is 'gain'.
'bar'+'gain'='BARGAIN'
(Other definitions for bargain that I've seen before include "Cheap acquisition" , "special deal" , "An agreement, or thing got cheaply" , "Good buy" , "Barter, negotiate" .)