Scots upset by prices (5)
I believe the answer is:
costs
'prices' is the definition.
('cost' can be a synonym of 'price')
'scots upset' is the wordplay.
'upset' indicates anagramming the letters.
'scots' is an anagram of 'COSTS'.
'by' is the link.
(Other definitions for costs that I've seen before include "Charges" , "Expenditure" , "Legal expenses" , "Expenditures, outlays" , "Fees" .)