http://www.svp.co.uk/
4 way case is 20p
6 way case is 29p
8 or 10 way case is 55p
Genuine Amaray single case is 20p
I've ordered from them many times and they've always been superb. They also have the best selection of DVD and CD media I've ever seen and cheap batteries too. Excellent value for money. Currently they're doing a 2-for-1special on Epson ink carts for those r300 CD printers too.