For Prime members only, Amazon offers the Timex Ironman One GPS+ Smartwatch
in Black/Gray or Gray/Lime Green for $199.95
with free shipping
. (AT&T Wireless
offers it in Black for pennies more.) That's the lowest total price we could find by $100. Features include an always-on Qualcomm Mirosol display, GPS, MP3 player, and water resistance to 164 feet. It includes a 1-year AT&T service plan but no heart rate monitor.