GPS tracking systems are easy to install. You can buy the ones over amazon or local security/alarm stores. The most it might cost is $2500 or less. It uses a prepaid sim and all you do is buy a phone card and send money to it using your phone. You will be able to get GPS, if the vehicle is parked or moving, speed it is moving at and even voice mode where you can hear what's going on in the cab.
The only thing different from GPS companies are that they provide aerial support if a car a stolen, has officers to retrieve the vehicle and partner with local police . All you need to do is sit and wait.. If you go with the cheaper method, yes you will know where your vehicle is if stolen, but waiting for response from local police and the hassle is tiring .