Uncle’s place, where you can get dubious material, I hear (8)
I believe the answer is:
pawnshop
'uncle's place' is the definition.
(uncle can informally mean a pawnbroker)
'where you can get dubious material i hear' is the wordplay.
'where you can get dubious material' becomes 'pornshop' (shop selling pornography).
'i hear' indicates a 'sounds like' (homophone) clue.
'pornshop' is a homophone of 'PAWNSHOP'.
(Other definitions for pawnshop that I've seen before include "Where one finds security" , "Premises for loans against personal property" , "uncle's establishment" , "Get ready here, leaving security" , "Uncle's place of business?" .)