There's currently a thread on discount from Oli but I think this worths a topic itself - Easier to find and more focussed.
O2 Sony Ericsson S500i Purple
* 2.0 megapixel camera with 4 x digital zoom
* MP3 player
* Picture blogging
* Memory stick Micro (M2) card slot
* Light effects and changing themes
Cheapest price online I've seen - even cheaper than many on eBay.
Free delivery for new customer with code R3HP.