Worst is bottled water or drinks, total waste of a snack credit. You can get free ice water from any CS restaurant or pay for a Coke if that's what you want.
Best are Dole Whip Floats at Aloha Isle, funnel cakes at Sleepy Hollow, sweet pretzels from Norway, anything at the bakery in France, beignets at the POFQ food court, basically anything that's under $4 and that you might like.