Bestbuy offers Rand McNally - Tire Pressure Monitoring System for $49.99 (orig. $79.99) with free shipping.

Product Description:
Make sure your tires are perfectly filled with this Rand McNally tire pressure monitoring system. Valve cap sensors on each tire transmit pressure information through a smart phone app and Overdryve, letting you know when it's time to add air. The small rechargeable TPMS receiver on this Rand McNally tire pressure monitoring system works in any vehicle.

Thanks Angie