The title of the thread is "most expensive cigar", so here's the top two I thought of.

The Cohiba Behike is selling around 470-500 and the 1492 has been selling for 500 from what I have heard.

Personally if I had 100 just to drop on a cigar, I'd get a cuban Davidoff (which I believe someone else has already suggested). If I was stocking up, and look for Opus, since you can spend 100 on that in a matter of seconds.