An Ebay seller has a watch style GPS unit for sale. Not rated as good as the Garmins but its a cheap GPS that you can use for almost any sport. I do not own this unit so I dont know if it is good or not but for the price it is hard to beat.

Schwinn GPS Tracking and Heart Rate Monitor (663176002263) | eBay

Amazon for comparison and reviews:

Schwinn 810 GPS Tracking And Heart Rate Monitor: Sports & Outdoors