The cab(s) I've found cost $100(AUD) I guess thats around 45 pounds these days? The trick is to try and find one where the cabinet is in good condition but the game inside is utter crap. One of those I found was a really bad Rolling Thunder clone (called Ranger -something-). The people selling classic games like Galaga/Galaxians/Pacman usually ask for a lot more ($1000+). Try your local classifieds under 'amusement/arcade'