The Five-dollar Prexie
The last President honored in the Prexy series was Calvin Coolidge, 30th President of the United States. He became President upn the death of Warren Harding, and was elected to a full term of his own afterward. His likeness is on the five-dollar stamp in the Prexie series, again from a medal produced by the U.S. Mint.
The five-dollar Prexie is the third value produced in two colors. It was issued in sheet format only. The first day of issue was November 17, 1938, and 9,318,026 were issued through 1956, the fewest of any denomination in the Prexie series.
There were no five dollar rates during the Prexie period. One solo cover, actually part of a package wrapper, is known, and it is not absolutely certain that the franking was not a convenience overpayment of twenty cents.
There are several parcel tags from a bank in Puerto Rico franked with one five-dollar Prexie and a postage meter. These are probably the next closest items to a true five-dollar solo use.