The ginger beer is interesting altho I hesitate to say that - alone - it would be one of my favorites. In combination with the Goslings rum, however, it is wonderful.
I'd suggest you call various places to see if they carry one or both products. In the leadup to the holidays (think: Thanksgiving thru New Years) they sometimes offer a package deal in liquor stores for the same price as just the rum alone. I've seen (and bought) the rum in a box with two bottles of ginger beer, but don't know what they might offer this year.