Seventy pence covers stamp (4)
I believe the answer is:
type
'stamp' is the definition.
(I've seen this before)
'seventy pence covers' is the wordplay.
'covers' indicates a hidden word (I've seen 'covered' mean this (the answer is covered up by the clue)).
'TYPE' can be found hidden inside 'seventy pence'.
(Other definitions for type that I've seen before include "The face" , "Write using a keyboard" , "Use a keyboard; sort" , "Category; use keyboard" , "get words on to paper?" .)