This tool can filter out water to make a lake or stream safe to drink! If you go hiking, camping or just like to stock up on survival gear, then this thing is cool to have.
LifeStraw Personal Water Filter
$17.02Price
I'd recommend you wait until the price is below $15 to buy it.
The LifeStraw is highly rated, but there is another one called Sawyer Mini that is also great. The LifeStraw one is a little less expensive, though :)