While you cant beat the price and accuracy of an location tracking device like this, here is an alternative to location positioning system GPS specifically useful for indoor usage. The smart developers at IndoorAtlas made use of varying earth's magnetic fields inside buildings to develop a product which enables accurate indoor navigation using smartphones with inbuilt magnetometer which are common these days. Not only this technology offers an cheap indoor location tracking capability for smart-devices but also mitigates the poor accuracy of GPS tracking when inside buildings.

Video demonstration of this new technology after the jump.