I have a set of 12 $20 FRNs with matching serial numbers. These are Gem Uncs from Series 1996 one bill for each Federal Reserve Bank.

The serial number on each bill is 00000765.

2000 sets were offered by the government. I was number 365 of 2000. The first 400 numbers were retained by the government.

I bought this set for $695 (I think) 4 years ago. I'd take $700 plus shipping

Currently a similar $10 set is available from the BEP for $575. However now the serial number are the 2000 highest possible numbers (99999999 would be the highest)