OK, I see one on OcUK for £170. Firstly do I assume that you plug it into the cigarette lighter and that powers it up and you remove it on leaving the car. Secondly you don't mean when motorways / roads are created you have to go and buy a new unit, do you? Excuse my ignorance (I'm an old git) and want to buy it for the lad.
More info would be appreciated however basic, please.