We're not saying break the rules, but sometimes the drink prices at games, carnivals, cruises, festivals, and resorts are outrageous. These are also good for camping trips. The Bibber Buddy kit comes in several sizes, each made of a BPA-free, food-grade, leak-proof, and puncture-resistant material. They're flexible and thin and won't be noticed by metal detectors, the makers say. Price: $14.99.