A couple of affordable truck trackers I've found

[gpsvehicletracking]

I wouldn't trust cheap solutions if I were you. From personal experience, the cheaper trackers are not reliable.

I would choose a gps vehicle tracking "solution" or "system" rather than a cheap device because a software solution is more reliable and robust than a device that can break at any point.

Some examples:
http://www.spireon.com/gps-vehicle-tracking/
https://en.wikipedia.org/wiki/Vehicle_tracking_system