Turn to an enlarged cash prize (8)
I believe the answer is:
rollover
But I can't explain it at all! Could you help me understand?
(Other definitions for rollover that I've seen before include "Turn in bed; allow (debt) to continue" , "big lottery prize" , "Deferring of payment" , "Carrying of a payment over to a later date" , "Reinvestment of funds r" .)