Difference in new paintings going up in price (8)
I believe the answer is:
contrast
'difference' is the definition.
(thesaurus)
'new paintings going up in price' is the wordplay.
'new' becomes 'n'.
'paintings' becomes 'art' (I've seen this before).
'going up' shows that the letters should be reversed in order.
'in' indicates putting letters inside.
'price' becomes 'cost' ('cost' can be a synonym of 'price'**).
'art' reversed gives 'tra'.
'n'+'tra'='ntra'
'ntra' put into 'cost' is 'CONTRAST'.
'in' acts as a link.
(Other definitions for contrast that I've seen before include "Compare to show differences" , "Dissimilarity of things compared" , "State of being strikingly different" , "Something completely different" , "Degree of difference found on tracts" .)