As we said, you don't have to BUY anything. You can make one.

I've bought two Spektrums, a DX6i and a DX7. Both came with binding plugs, and I seem to recall that the receivers came with one too. So, if you didn't get one, chances are you either lost it or it was taken out of the box for some reason. Think about it. Would they sell you a transmitter/receiver combination that needed a binding plug and not provide one for you? I think not.

CGr.