Challenge air conditioning price (6)
I believe the answer is:
accost
'challenge' is the definition.
(I've seen this before)
'air conditioning price' is the wordplay.
'air conditioning' becomes 'AC'.
'price' becomes 'cost' (synonyms).
'ac'+'cost'='ACCOST'
(Other definitions for accost that I've seen before include "Tackle" , "Meet and greet" , "Approach and address boldly" , "Approach boldly or aggressively" , "Approach, stop and speak to" .)