GPS tracking

[Aruba1]

I know there are a lot of threads out there that owners reporting to have ignition cutoff switch, etc. But I am afraid that someone wanting to steal my truck can have it towed and that beats the purposes of having these old school tricks. Does anyone has GPS tracking on their trucks? I am talking about just those little devides that you can install in your truck (under the dash, seat, engine compartment, etc) and that allows you to track the location of your truck. I see them on ebay going from anyone of $25 to over $200.

Worst case I have an old iphone 4 that I can hide in my truck and get the Track my Iphone service that is free. And hardwire it so it can always be charged. I can get a cheap basic plan for $10 or $20 a month and 10 cents of MB of data when I have to track my truck. Anyone? Any ideas? My truck is not a concours restoration but having a 5.3L, NV4500, 19.5 wheels, etc, it has some value for me and probably for some thieves.