The solution consists of a Wallet TrackR, a small device that fits in a credit card slot of your wallet, the device is operated by 2 flat watch-batteries enough to last months the other component is an app on your smartphone [iOS, Android]. The two items need to be nearby, separate them at Low-Energy Bluetooth out-of-range distance will trigger notification on both smartphone and the TrackR.
Around the house, the smartphone app will help you to locate the wallet with the map and audible sound. If you can not find your phone and you have your wallet at hand, you can tap on the TrackR device, your phone will ring, even it is on silent mode. Multiple TrackR devices can paired to your phone. You can purchase the Wallet TrackR HERE ($30 for 1, $40 for 2)