Discount rate doesn't include rustic present (6)
I believe the answer is:
donate
'present' is the definition.
(donating is a kind of presenting)
'discount rate doesn't include rustic' is the wordplay.
'doesn't include' indicates named letters should be taken away.
'discount'+'rate'='discountrate'
'discountrate' with 'rustic' taken away is 'DONATE'.
(Other definitions for donate that I've seen before include "Fork out" , "Give as gift, say blood" , "Give (eg to charity)" , "give in kindness" , "Give charitably - say blood" .)