Pins up something cheap (4)
I believe the answer is:
snip
'something cheap' is the definition.
(snip can mean a bargain)
'pins up' is the wordplay.
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'pins' backwards is 'SNIP'.
(Other definitions for snip that I've seen before include "Cut with shears" , "Bargain (informal)" , "Cut back" , "nick)" , "Bargain - crop" .)