New (no box) Queen Bee .074 - $80 SOLD ON EBAY

Prices seem about right, Jacob. I did a search just before you posted, and could find none, but my search was within the Bay. Regarding Bay fees, I noticed on Stunt Hangar that a number prefer to sell their engines outright, benefits both buyer and seller.

It's a strange Cox engine. Other Cox engines were light weight and powerful. The QB is heavy and powerful, but mine was cantankerous, why I never put it in a plane. Heavy is never a good thing, especially for a half-A plane. Always made me wonder why Cox didn't simply slightly upsize the 290 product engine and go with their standard lightweight exhaust throttle muffler. Then, they would have had a winning combination.

Now it is a collector, but then I think for these reasons is why it never sold well, which also affected demand.