2013*888 via eBay offers this Waterproof Bluetooth Activity Tracker Smart Watch in several colors White (for $21.59 with free shipping. That's $10 under the lowest price we could find for a similar watch. It's compatible with a range of iPhone and Android phones, tracks steps taken, sleep, and heart rate, and features alert notification, Bluetooth, and an LED display.

Note: This ships from China and may take up to five weeks to deliver. Prices have risen slightly for the remaining colors to $22.99.