I bought it from von-phone last year. With shipping I paid a total of $44.95 USD, selling for $30 USD.
Skype users:- This adapter will liberate you from the headset and unchain you from your computer. I used mine with a cordless phone and it's incredible to be able to be talking on Skype while walking around the kitchen, out on the balcony, etc. I was one of those formerly chained to the computer, so I could really appreciate the freedom that comes with this tool.
For those of you who haven't discovered Skype yet, you don't know what you're missing! SkypeOUT is pretty good, but SkypeIN....man! SkypeIN just totally ROCKS!