Makes bigger offers (7)
I believe the answer is:
extends
I believe this is a double definition.
'makes bigger' is the first definition.
'offers' is the second definition.
('extend' can be a synonym of 'offer')
(Other definitions for extends that I've seen before include "Enlarges" , "Widens" , "Reaches or stretches out, say the hand of friendship" , "Lengthens" , "holds out" .)