Ten cents circulating in the Midwest (4)
I believe the answer is:
dime
'ten cents' is the definition.
(I've seen this in another clue)
'circulating in the midwest' is the wordplay.
'circulating' says the letters should be written backwards.
'in' says the answer is hidden in the clue.
'emid' is hidden within 'the midwest'.
'emid' written backwards gives 'DIME'.
(Other definitions for dime that I've seen before include "Small American coin" , "Something round and silvery" , "10c coin" , "Ten-cent coin in America" , "Ten cents in USA" .)