I got mine from Amazon for £88.58 including delivery, but not impressed that it turnes out to be an import.
It had a UK power leade loose in the packaging. The actual unit is brand new and sealed, but not happy as it was for a present. After reading through various forums I have decided to keep it as the power supply is universal and the PAL/NTSC is controlled by the iTunes account which its registered to.
That's the only way UK sellers can seriously undercut MSRP.
Last time I visited my parents in the UK I brought one over from the states. It was significantly cheaper even with US sales tax added. Once paired with the UK iTunes store, and an appropriate UK mains cable, grey import ATVs are all but indistinguishable from white market ones.
Another case of "Rip off Britain"