Tries on pants off the shelf? (2-5)
I believe the answer is:
in-store
'off the shelf?' is the definition.
(available in a shop)
'tries on pants' is the wordplay.
'pants' indicates an anagram (UK informal term for 'nonsense' or 'rubbish').
'tries'+'on'='trieson'
'trieson' is an anagram of 'IN-STORE'.
(Other definitions for in-store that I've seen before include "Coming" , "Ahead" , "Awaiting one in the future" , "About to happen" , "Within a shop" .)