Follow United, again in the money for winning (6)
I believe the answer is:
pursue
'follow' is the definition.
(to pursue is to follow or chase)
'united again in the money for winning' is the wordplay.
'united again' becomes 'u' (I am not sure about the 'again' bit.).
'in' indicates putting letters inside.
'the money for winning' becomes 'purse' (money to be won in a contest).
'u' going into 'purse' is 'PURSUE'.
(Other definitions for pursue that I've seen before include "Search for" , "Try to win" , "Follow, chase" , "Be engaged in - hunt" , "Follow up on or go after" .)