Suzy,
in T&T you can find Marlboro, Dunhill, Du Mauriet, Pall Mall and some rough fisherman typ cigarettes
B&H are no longer produced or sold here.
Before you leave Tobago, you will have access to duty free shops in the terminal building.
Those shops may sell B&H, not sure. They definately sell the brands mentioned above.
Normal shop prices for a pack of cigarettes (20 cigarettes) are around TT$ 18.00
Duty free is not significantly cheaper but still MUCH cheaper than anywhere in Europe or UK.