If you purchased a print card at the library (a $5 vending card at the Service Desk: $4.25 of printing + 75¢ for the card) - you can add money to the card at any time by following these instructions:
Go to this site: MSU GET Funds
Follow the instructions at the site: enter the number on the back of the print card in the MSU ID field making sure to enter the number 9 at the beginning of the ID number instead of a dash (-). Enter "Printing" in the First Name field and "Library" in the Last Name field.
Select continue and follow the rest of the steps to finish adding funds.