Brand new probably not, ebay will be the best place to get something if you don't mind it being secondhand. http://shop.orange.co.uk/shop/show/handset/sagem_my401x/detail/pay_as_you_go Thats the closest thing to £50 with a camera.
i agree, brand new is virtually impossible, but you could try the reconditoned section http://www.orangeaccessories.co.uk/reconditioned_mobile_phone/all.html have bought reconditioned from orange before, its basically the handset battery and charger