Picked up an official Sony AC adaptor in Sainsbury's the other day for £10. Scanned through the till at £17.99 but operator manually reduced price as it as labelled at £10.
Seems to be online for around £17.99.
For those that don't know this allows you to charge ps3 accessories via the mains instead of having them plugged into the ps3 USB slot. Works with the new move controllers too, far more versatile than having a move specific charging dock.