Yes, they are expensive. Here's the N.A. KOSO website with US distributors who all show list prices on their websites too:
http://www.kosonorthamerica.com/koso_anglais/toutes.htm
but they are much cheaper on UK and German ebay which is where I got mine but I got seriously raped on shipping charges by the German vendor. In hindsight, I should have asked a Euro or Brit Viffer to purchase/ship them to me.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...p;rd=1&rd=1