And, How about the multi $10's And $20's Half the book price like the 5's?
Or do they retain their book value better than 5's?
... well for common notes its pretty much the same picture I believe. At least the $5.00 and $10.00 were replaced by Journeys in 2000 and 2002. The fives have a colourful history of coloured BPN, replacements, and change-overs (& exceptionally rare "good-overs" like the B/T HNB).
The only $10 Birds anybody seems to be keen on are the T/C BDH (a rare change-over), and B/T BDP inserts (4.44-4.46), ATX, BDZ (.000-.04). I'm a little bit surprised at all the fuss over the non-designated inserts...when the Bonin Thiessen ATX is so hard to find, and under-rated/valued IMO. It is also the last designated replacement of its kind (same with $5 B/T ANX, $2 B/T EBX)
Only the ealier T/C (I with or without serifs) or B/T with no BPN (eg EVH) $20 seem to be the most popular. The Birds $20 didn't get phased out until 2004 (or after) so everyone has plenty to spare. Look at the AIX or EIX $20 replacements-- not much excitement there (yet they're the last replacements of their kind). Seems like more people are interested in the non-designated inserts. I guess people stashed the X notes away and were caught off guard with the non-designated inserts that are proving harder to find.