Which Permasharps are you after?
The Perma Sharp Super or the Gillette 7 O'Clock Permasharp Stainless?
For Perma Sharp Super (Turkish writing on the packet) I bought mine from 'The Modern Man' when they were on sale, but I think they have a 10% new customer deal and shipping is included.
For the Gillette 7 O'Clock Permasharp Stainless on Ebay UK sellers with deals 200 at £13.