Back about 20 years when I started selling off all my early 1970's stuff (pre-BAR), I had an Enerjet F69 - still sealed in the box (at one time they came packaged in a display box sealed with shrinkwrap). At the time ebay wouldn't accept rocket motors so I put it up on another rocketry site.
Two guys got in a bidding war for it and it sold for close to $200! I was shocked...

I've still got a couple Enerjet motors around here somewhere (E's IIRC). I may fly one just for old time's