They will allow (I believe) 1 - 12pk of beer or 1 liter of hard stuff/wine per adult.
You can actually buy US branded beer (Coors light, Bud) in RP for less than in the US.
6 packs of Corona, Pacifico, Dos XX, Sol are 80-88 pesos ($4.25) Coors light and Bud are about the same at Super Ley.
I...