A single page (one side) of a black & white printout costs 1 credit. A single color printout costs 5 credits.
Whatever credits you don’t use roll over to the next term–so if you have 83 remaining after Fall term, you’ll have 308 when Winter term begins. However, accounts are wiped clean before Fall terms, and everyone starts again with 225.
Related posts: Save paper by printing double-sided ; Print multiple PowerPoint slides to a single page