It varies from chapter to chapter. I bought a jewelled badge for around $200. Still also have my regular badge which comes with your initiation cost (I think a replacement is like $49).
I was at our Oklahoma University chapter (or they were here, I don't remember) but one of their members saw my badge and asked me (paraphrased) what I did to earn that?
I just bought it -- was willing to shell out the $$
It's something that apparently they give to those that earn the distinction. It's just a tradition that varies between chapters. Saw a lot of them at our national convention though.