A large amount of cement on sale (4)
I believe the answer is:
tons
'a large amount' is the definition.
'of cement on sale' is the wordplay.
'of' says the answer is hidden in the clue.
'TONS' can be found hidden inside 'cement on sale'.
(Other definitions for tons that I've seen before include "Loads (sl.)" , "Lots" , "A lot" , "Each is equivalent to 2240 pounds" .)