Yeah, there are 31 signed index cards of Marquard on ebay now, starting at $19.99. This beauty can be had for $29.99:
http://www.ebay.com/itm/RUBE-MARQUAR...item4d02c9c556
The question is really how much does that amazing inscription add to the value of an otherwise $30 autographed index card? At that point you're paying for content more than signature. The value of content is extremely subjective.
When I bought this Snodgrass collection, the letter wasn't much more than a throw-in. But, because of the content, and reference to a signed "Cigarette Photo card", it is more or less priceless to me. That's my subjective value.
