Samoa snacks is more.... snacks. Chips, cookies, pretzels, candy, small food and housewares "gift items", and liquor, beer and wine. I seem to remember picking up a box of Entenmann's donuts there once.
Captain Cook's prices are probably about the same as in the parks. It's not a "destination" or a fine dining experience, but it works when you're hungry and in a hurry! They have an ice cream cooler with an assortment of treats, including Mickey bars. Assorted breakfast pastries and cereals. Milk and juices, fountain beverages. Cold sandwiches, fruit, salads. Burgers and pizzas from the grill.