Which gps-enabled watch? topic

Hi, all.

Getting into mountain biking and don't want to bust my cell phone, so looking for something that has gps to track speed, distance, etc., while not too heavy on the wallet.

Suggestions? Looked up one ebay and came across this thing:

http://www.ebay.com/itm/Bluetooth-Sm...item1e915454d3

Also have some used Lg G watches for around the same price.

Thanks!