Resell quickly (4)
I believe the answer is:
flip
'resell quickly' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for flip that I've seen before include "Spin in the air" , "Turn quickly over; sort of chart" , "Toss or flick in the air" , "Go crazy - other side" , "B-side" .)