While bottles of alcohol are cheap compared to the states the same can't be said for cocktails on the island. Example: Malibu Rum was $12.99 at airport (typically higher than other parts of island) while the same bottle was $28.99 in my local liquor store. Finlandia Vodka cost us $11.99 but is twice the price here in NY.

Cocktails at restaurants/bars are not cheap considering most cocktails, wine are $8 and higher. Two for one and happy hour does in most cases significantly reduce the price of a drink.

Yellow Sub on Orient offers Happy Hour as does Dinghy Dock in Oyster Pond which are closest to your area. Oyster Pond is by no means close. I haven't stayed in Grand Case in years so don't know if Blue Martini or others offer happy hour.