Discount arranged for pipes? (8)
I believe the answer is:
conduits
'for pipes?' is the definition.
(pipe is a kind of conduit)
'discount arranged' is the wordplay.
'arranged' indicates anagramming the letters (letters rearranged).
'discount' with letters rearranged gives 'CONDUITS'.
(Other definitions for conduits that I've seen before include "Passages for wires or water" , "Discount for liquid channels" .)