LifeStraws are great backpack staples for hiking, or nice gifts for the outdoorsmen in your life. And right now, they’re just $15, which is about as cheap as you’re likely to see them, with a few short-lived exceptions.
If you aren’t familiar, these allow you to sip directly from basically any source of fresh water you find in nature. Hopefully you never need one, but if you like to spend time outdoors, it’s worth keeping one in your bag.