Down payment is raised inside store (7)
I believe the answer is:
deposit
'down payment' is the definition.
('deposit' can be a synonym of 'down payment')
'is raised inside store' is the wordplay.
'raised' says the letters should be written backwards.
'inside' indicates putting letters inside.
'store' becomes 'depot' ('depot' can be a synonym of 'store').
'is' back-to-front is 'si'.
'si' placed inside 'depot' is 'DEPOSIT'.
(Other definitions for deposit that I've seen before include "Put down or leave something" , "Place" , "part-payment" , "fur, possibly" , "Topside (anag) - put down" .)