Patozon via Amazon offers the Mpow iSnap Bluetooth Wireless Camera Shutter Remote Control for Mobile Devices for $14.99. Coupon code "MPOWBLUE" cuts it to $9.99. Plus, Prime members receive free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, it adds $5.07.) That's $18 off and the lowest total price we could find. It's compatible with most Apple and Android smartphones and tablets, and features a 30-foot range. It requires one CR2032 battery.