Just saw this on Maplins ...under 10 pounds for a wireless usb phone, but Maplins are also doing free delivery on there sale items!
Not sure , but its worth checking out for a cheap VOIP solution that doesnt tether you to your computer (I believe you still need to have a computer for the USB transmitter though).
dont forget with Quidco 4% cashback, and you can also pay with paypal!
Sorry if this is a lame deal....my first post! Be gentle.