It's nothing like £10 if you get several from online stores like http://www,storeshop.com/zap_cap.html

Like from a catalog, postage and warehouse saleries etc have to be covered and it's sold at rcccommended retail price.

The price you paid in vancouver was probably not for a genuine zap cap.

The rights to zap cap have recently changed and there was a retail vacuum for
a while. Zap caps are now being successfully sold into retail.