OK, here's a quiz. What started at $4.95 and five days later turned into one penny shy of $298? No need to guess, because it is a (dare I say rare?) Dear Doctor postcard that sold on eBay on September 27, 2012.

eBay seller "mcmichiganinky" placed this Austrian card for sale on September 22 with the following description:

"Picturing the "Spanish Court Riding School", this Card from Abbott Labs is one of a series advertising their PENTOTHAL (thiopental) product. The Stamp tied is Scott Catalogue number 622A, with a postmark date of September 27, 1968. The Card shows minor edge wear. Successful Bidder pays $1.00 postage & handling. Foreign buyers pay $2.00 postage & handling.

"THIS IS ONE OF SEVERAL ABBOTT LAB CARDS WE'RE LISTED ON EBAY TODAY AND YESTERDAY! FROM AN ACCUMULATION THAT HAS BEEN "HIDDEN" FOR YEARS, THERE ARE CARDS WE'VE NEVER SEEN BEFORE AND VARIATIONS OF POSTMARKS, STAMPS AND IMAGES FOR SEVERAL COUNTRIES. CONDITION IS GENERALLY FINE WITH A FEW CARDS SHOWING MOSTLY MARGIN WEAR FROM MAIL PROCESSING OF THE (THEN) NEW, LARGER CONTINENTAL SIZE CARDS."

Indeed, this card has only been reported once and although on my master check list, had an improper description. As you can see it features Austria's famous Lipizzaner stallions in formation.

Four separate bidders placing 9 bids went after this card with a vengence. Take a good look at the last two bids for $292.99 and $297.99. Both sniping offers took place at exactly the same time to the second, just six seconds before the close!

The seller obviously knew he had some special cards based on his description. This one eclipsed two other Dear Doctor record prices for cards that sold on eBay the same day. A Spanish card postmarked November 29, 1967 depicting a night view of Madrid went for $232.50 (4 bidders, 8 total bids), and a Peruvian card showing "Landscapes of Peru" at Paca Lake hammered down for $221.50 (5 bidders, 12 total bids). And no, the same bidder did not win all three! Many of us were watching these and the seller's other lots over several days with amazement. More "common" cards from his cache sold in the $40 to $90 range.

What else lurkes out there awaiting us?