What is a paper currency collector called?
Curency collecting is the field of Notaphily which refers
specifically to the collecting of "bank notes" or currency as we
call it. Sometimes collectors in this field are also called "rag
pickers" particularly if they are collecting low grade currency,
grading refering to the condition of preservation of the note.
Collectors can be called Notaphiles which is not dissimilar to
Bibliophiles (the book folks). The overall field which would
include things like coins (numismatists), bank notes (Notaphiles),
old stocks and bonds (Scripophilia) and stamps (Philately) is
usually generally, and incorrectly, referred to as Numismatics.
This comes from the Greek "Nomisma". And a bit more to help you
interpret the Greek: "Scrip" designates ownership right. "Philo"
designates "love of" or "to love". "Ateleia" designates "an
exemption from payment". There are many more but that should
suffice for the moment.