The HSMP does provide soap and shampoo. As Flog said, the soap is 'fun'size (btw when did 'fun' become a synonym for small?), but if you see one of the people who clean the rooms, you can always get some more. Or, if you are out all day, ask at reception. They all speak very good English, if you don't speak much Spanish. If you want your usual brands, you can probably get them at one of the supermarkets.