Cafe's rent low but rising (3,4)
I believe the answer is:
tea room
'cafe's' is the definition.
(I've seen this before)
'rent low but rising' is the wordplay.
'rent' becomes 'tear' (synonyms).
'low' becomes 'moo' (both can mean to make a cow noise).
'but rising' says the letters should be written in reverse.
'moo' reversed gives 'oom'.
'tear'+'oom'='TEA-ROOM'
(Other definitions for tea room that I've seen before include "Small restaurant or cafe" , "Where light refreshments are served" , "Place in which a cuppa is served" , "Place for light refreshments" .)