Share costs (2,5)
I believe the answer is:
go dutch
'share costs' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for go dutch that I've seen before include "Pay your own share of bill in Holland?" , "to pay only half" , "Share costs equally" , "Share expenses - in Holland?" , "Pay for one's own entertainment - in Holland?" .)