Expression of delight to get trade bargain (5,3,4)
I believe the answer is:
wheel and deal
'expression of delight to get trade bargain' is the definition.
I can't judge whether this definition defines the answer.
'expression of delight to get trade' is the wordplay.
'expression of delight' becomes 'whee' (I've seen this in another clue).
'to get' becomes 'land' (landing is a kind of getting).
'trade' becomes 'deal' (synonyms).
'whee'+'land'+'deal'='WHEEL AND DEAL'
Can you help me to learn more?
(Other definitions for wheel and deal that I've seen before include "Engage in unscrupulous commerce" , "be an operator" , "Engineer" , "Engage in shrewd bargaining to advance one's own interests" .)