depends on what kind of chocs and brands.
And certain shop may have offer cos :-
1. they are main agent for that brand
2. short-shelf life
3. over stock
4. promotional offer by choc manufacturer.

Best is try shop around in Kuah town
Haji Ismail Group Sdn. Bhd
Saga Shopping Centre
Zeno Duty Free

Teoh Soon Huat is kind of on the fringe of Kuah Town but if you have your own transport do take a look.