This is a very minor misprint that is not especially valuable. Collectors call this a stuck digit or a gas pump error. On the two dollar bill below it is most noticeable on the last 3 in the upper right serial number. The low serial number occurs because the numbers on the serial number roller gets stuck or jammed. For those of us who remember the non-digital gas displays, we can see why this misprint is sometimes called a gas pump error.
Minor examples of this error might be worth a few dollar over face value. These are neat to see, but they aren't rare.