Cheap lawyers win (7)
I believe the answer is:
bargain
'cheap' is the definition.
(sold at a bargain price)
'lawyers win' is the wordplay.
'lawyers' becomes 'bar' (the bar can mean the legal profession).
'win' becomes 'gain' (synonyms).
'bar'+'gain'='BARGAIN'
(Other definitions for bargain that I've seen before include "Special offer" , "Agreement, deal" , "Advantageous purchase" , "Discuss terms for buying" , "Good-value purchase" .)