There's this company that has created these nifty little Bluetooth-powered tags that you can attach to things to help you find them later on. Say you lose you keys all the time, want to be sure you don't misplace your laptop, or can't risk losing your backpack on a college campus—just slap one of these tags up there and you should be good to go. That's the idea behind Tile, whose little Tiles now work with Android.
Your phone connects to a Tile using Bluetooth Low Energy, and it can locate a nearby tag in two ways. Either the app notifies you that you're getting close, or you can tell the tag to play a chime. Either way, you have to be within 100 feet to have any luck. There's no built-in GPS, so you can only find what you can reach with Bluetooth.
At those times when you wander too far away from something and have no idea where it is, you can pull up the last known location on a map. If that's not where the thing is anymore, you can call on other Tile users to help locate your stuff.
The app is free to use, but you need to purchase a Tile or two to get any use out of it. Prices start at $25 for one, but you can get a pack of four for $70, a pack of eight for $130, or a pack of twelve for $180. Whichever way you go, these things aren't cheap, and their batteries are meant to last a full year. At that point, it's time for a replacement.