Everyone reading this (hopefully) brushes their teeth, so this Amazon sample box should be a no-brainer. $5 gets you a trial-sized floss, two Crest 1-hour express whitestrips, and 2.5 ounces of toothpaste, which is a perfect size for flying.
You should know the drill by now, but once you get your box, your Amazon account will automatically be credited $5 to spend on dozens of oral care products. Some of them are things you’d buy anyway, so you’ll essentially get the sample box for free.