Once again it is not worth much more than a shoe shine unless you invent and produce the actual GPS Car Tracker. Domaining is a bit like the Stock Market in the sense that 'this is not a savings account'.
I'm not trying to be a Killjoy papeter, but you must have a physical product to work in tandem with the Domain Name, unless you are working with Services and/or Software.
GPSCarTracking.co.uk 'out-of-the-box', undeveloped.. $250 max