Are you a money collector? I sell radar and repeater notes on ebay. Here are my auctions. Seems funny to those of you that don't know anything about money collecting. I'm fairly new at it myself, but there is such thing as note buying.
These are just a few. I have a lot more. The idea is to aquire uncirculated notes with particular series of serial numbers, different combos are worth more than others. What I have here are just common.