Electronic Alarms and Home Security Devices - GPS or other tracking method

anyone kno any cheap tracking devices. the best i found so far are child locators which can locate a device the child is weaing. the purpose is mainly to track something if its lost or stolen, could catch some thieves. i cannot find anything under $200 and im not rich nuff to buy those devices either, i need this mainly for bicycles as they are somewhat expensive,yet easy to be stolen, regardless of the quality of locks. Another item is my laptop, which is wayy too expensive to loose, but if stolen at gunpoint, using a tracker like this could help me locate the theives so the authories can do their job while istill have mny laptop. If anyone can help with this i would be very greatful because this is a problem many of us face everyday. thank you.

A recent discussion on this topic can be found at http://forum.doityourself.com/showthread.php?t=301429