These postal notes are from a bygone era and probably should never have left the official holders ( First National Bank of Wallace / US Postal Service ) after having been redeemed for their actual cash value.
These were used by post offices around the country to represent small amounts of money ( under $1 ) that were being sent by people buying postal money orders. The clerk would affix and then postmark these stamps.
Each of these postal note stamps is attached to a numbered stub showing the amount of cents. The reverse features a "pay to the order stamp" and official postmark of Wallace, Idaho, all in very nice condition.
The postal note system was discontinued on 31 March 1951.