I just wanted to add that one must be careful about putting too much
emphasis on the price paid for a single item, especially if sold at
auction.

I once found a roll on eBay that I really wanted, and thought was
"rare".  I exited the bidding when it reached $75.00.  Over the next
year (probably due to other sellers seeing the price it sold for)
several more copies of the same roll showed up.  In the end, I got
the same roll for only $3.00.

Quite often misinformation, hype, and lack of knowledge by the buyers,
combined with the auction "format", can lead to ridiculously high
prices.

John Miller
Saint Paul MN USA