My nomination goes the Roadchef near darlington, machines tucked away in a corner. Had 4 machines, 3 were emptied, and the 4th was apparently in the process of being emptied, i went to see what was there whilst mate got a burger, popped my head round the door to see 3 machines with IOU's and 3 large scruffy guys just stopping what they were doing and staring at me till i realised that meant leave immediately.
With machines like Duff Beer Guide, Wildfire and Battleaxe, it's quite easy to blag a few quid in Keele. Not to mention TIJ2 and Homer's Meltdown on the other side.