Not sure this is going to work with the Rpi but I found the ILUV IAD217BS power supply which appears to be a clearance on the Currys website. It's got 3 x USB outputs 1 of which can supply 1A with the other 2 supplying 0.5A. It's £3.97 delivered and as it ends in a 97 then its a clearance item so be quick. It doesn't appear to come with a micro USB cable so one will need to be purchased separately.
http://www.currys.co.uk/gbuk/iluv-iad21 ... 5-pdt.html
Also spotted is the international version of this at the Argos ebay outlet store which includes travel adapter connectors and its £5.98 delivered.
http://www.ebay.co.uk/itm/ILUV-IPAD-IPH ... 0560142835
NOTE : Just to reiterate I do not know whether these will work with the RPi but I've bought the former to test.
Also a word of warning I bought 2 x cheap micro 1A USB chargers from ebay supplied from HK. On arrival one didn't work and the other died with a very loud bang and took my electrics out.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0656849772
Seller refunded promptly and apologised.