Get a 12-pack of small tubes of toothpaste for air travel

For a variety of reasons, most hotels don't supply toothpaste in rooms. (Here's an article from Slate that explains why.) And you can't take a standard-sized tube in carry-on luggage because the toothpaste police at the airport will confiscate it. You can buy a 12 pack of 0.85-ounce tubes of Crest on Amazon for $11.97.

(For more tips and recommendations, check out a book I co-wrote, called Recomendo)