I have a $20 bill that is missing a minor portion of the ink on the back. You can see an imprint where there is supposed to be ink, but there is nothing there. The error covers approximately 1/3 to 1/2 an inch from the edge into the printed area of the bill. As far as condition, one corner is slightly bent, and there is a crease down the middle. No other major problems. I don't have any pics of it yet, but it looks nearly identical to this; http://cgi.ebay.com/1993-50-FRN-NY-ERROR-INSUFFICIENT-INK-CGA-58-AU-/350298736301?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item518f6e86ad What's the approximate value? EDIT: It's an earlier series, 1993, I think.
Haha, I meant the printing error. It has the back of a $20 note, just the same error as that $50 note.
Ebay completed auctions show one completed sale for $100 that's missing almost half the ink on the back. So I'm gonna go ahead and value it at approximately $50, as a complete guess.
Dr. Barts US Paper Money Errors lists a 1993 $20 insufficient ink just like that on p.85 for F=$50 EF=$75 CU=$100 must be more than a handfull of that particular year.