Inflates charges after sales occasionally (7)
I believe the answer is:
aerates
'inflates' is the definition.
(to aerate is to fill with air)
'charges after sales occasionally' is the wordplay.
'charges' becomes 'rates' (rate is a kind of charge).
'after' says to put letters next to each other.
'occasionally' means one should take alternating letters.
The alternating letters of 'sales' are 'ae'.
'rates' after 'ae' is 'AERATES'.
(Other definitions for aerates that I've seen before include "fans" , "Pumps carbon dioxide into" , "Brings gas" , "Adds carbon dioxide to liquid under pressure" , "Puts fizz into a drink" .)