If you're not big breakfast eaters, I would pack some cereal bars or oatmeal to eat in the morning. Some people use their snack credit for breakfast, I don't like to do that.
I like to save the snack credit for good snacks-Dole Whips, Goofy's Candy, Main St. Bakery, etc.
Don't use your snack credits for drinks-unless it's a Dole Whip Float or some specialty drink. You can get ice water from all of the CS for free. If you don't like the taste of Orlando water bring some flavor pkgs to flavor the water.