Set free rent with facilities barely used (3,5)
I believe the answer is:
let loose
'set free' is the definition.
'let loose' can be an answer for 'free' (I've seen this in another clue). I am unsure of the 'set' bit.
'rent with facilities barely used' is the wordplay.
'rent' becomes 'let' (I've seen this in another clue).
'with' means one lot of letters go next to another.
'facilities' becomes 'loo' (I've seen this in other clues).
'barely' indicates the central letters (the word is bare of its external letters).
The middle letters of 'used' are 'se'.
'let'+'loo'+'se'='LET LOOSE'
Can you help me to learn more?
(Other definitions for let loose that I've seen before include "Release, remove restraints" , "Set free from restraint" , "Set free, release" .)