Anywhere in the Library where a person can break a $50 bill? Any place on campus?

There is no place in the Library to get change. The Procrastination Station does not break bills, but might have the cash available if you were to actually purchase something. Have the Patron ask before they do it though.
As for on campus most places will need you to buy something in order for them to break a bill. You can also try the UMass/5-College Federal Credit Union in the Campus Center but you need to be a member for them to give you change.