I'm using a Masterplug single USB 1.0A PSU purchased at Sainsbury and it works well. Sainsbury have their own brand which looks identical and is slightly cheaper but I've not tried one. A similar Masterplug black coloured one is on Screwfix (Sainsbury sell the white ones).
http://www.screwfix.com/p/masterplug-us ... lack/45307
I have also used my 4 port Belkin powered hub F5U404-BLK which I can use one port to power the Raspberry Pi and I'm using 2 of the other ports for a wireless keyboard & USB memory stick. It's a tiny hub so trying to plug 4 items into it isn't great unless they are slim or you use an extension USB cable - but it's a neat solution to give sufficient power to the Pi and powered USB ports as well using a single 230V plug / supply rather than one supply for the Pi and another for a powered hub.
If you've an iPod / iPad / Kindle power supply these may also work.