ANSWER 1: You can add money to your Print Account by logging into your account and navigating to Add Credit on the left sidebar. You can also visit the Library Front Desk during staffed hours.
ANSWER 2: If you know you have money on your account, it may be because the printer is trying to print the documents in color and apply that greater charge. When logged into the printer, use the touchscreen to select Print Release, then select the specific jobs and check the box Convert to Greyscale. This will update the price in the top-left corner.