Look through last of my cash (5)
I believe the answer is:
ready
'cash' is the definition.
(I've seen this before)
'look through last of my' is the wordplay.
'look through' becomes 'read'.
'last of' says to take the final letters.
The final letter of 'my' is 'y'.
'read'+'y'='READY'
(Other definitions for ready that I've seen before include "Willing (to do something), prepare" , "game?" , "Primed" , "rough companion" , "In addition" .)