As one of its daily deals, Amazon offers its Prime members the Polar H7 Bluetooth Heart Rate Sensor & Fitness Tracker in Black, Blue, or Pink for $34.95 with free shipping. (Non-members can pad their order to $35 or more to qualify for free shipping; otherwise, shipping costs $6.72.) That's $2 under our Prime day mention and the lowest total price we could find by $18. It's compatible with Android and Apple devices. Deal ends today.