Valuing mostly art? Unlikely — he's got money but no taste (9)
I believe the answer is:
vulgarian
'he's got money but no taste' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'valuing mostly art? unlikely' is the wordplay.
'mostly' means to remove the last letter.
'unlikely' is an anagram indicator.
'art' with its final letter removed is 'ar'.
'valuing'+'ar'='valuingar'
'valuingar' anagrammed gives 'VULGARIAN'.
Can you help me to learn more?
(Other definitions for vulgarian that I've seen before include "One with ostentatious bad taste" , "boorish type" , "unpleasant sort" , "upstart" , "Unrefined individual" .)