ok, so go to your local supermarket and get the cheapest pay as you go mobile phone and a car charger.
Take it home, open an account with verilocation.com or similar, register the phone, and set it to silent.
plug the charger in, tape it to the back of the phone, solder a wire to the center of the charger (pin) and one to the side contact.
depending on your application - car or plant - find somewhere to power it from - the permenant live on the back of the the radio is good, or somewhere in the cab. wire it in, hide the mobile and there you go. a simple basic tracker.
not too accurate,
Seriously tho, for approx £15, you can roughly track anything.
We tracked our vans. one got stolen. we told the police where it was to within two streets. They didnt go. we went. we found it. we called them, they didnt come. we gave up and recovered it home. we were stopped on the way home and arrested for theft. They let us go, almost immediately, but its a perfect example of police work.
Dont use the charger, just toss the phone in the back of the partners car, on silent and fully charged. you can track them for 4-5 days depending on the phone.
My missus caught me skiving work that way.