Reduced price for lettuce (3)
I believe the answer is:
cos
'lettuce' is the definition.
(cos lettuce is a kind of lettuce)
'reduced price' is the wordplay.
'reduced' means to remove the last letter.
'price' becomes 'cost' ('cost' can be a synonym of 'price').
'cost' with its final letter removed is 'COS'.
'for' is the link.
(Other definitions for cos that I've seen before include "Chief of Staff" , "vegetable?" , "in the Dodecanese?" , "foreign island" , "naturally having longer leaves than most" .)