Thirsty,
I spoke with Ali, the bartender at Iguana Bar and Kurt , the former bartender/manager at Dingy Dock. They say Coors Light is readily available on the island but Miller Lite can be a challenge. They recommended Caribbean Liquor and Tobacco in Phillipsburg. I saw Coors Light at Le Grand Marche at the round about in Phillipsburg for about the same price I pay for it in the states. Hope this helps.