Most students purchase their Packback's access on the Packback's website, therefore, paying the direct cost of $25 or lower (using Curiosity Credit program) per community that they join.
Occasionally, students purchase their community access through their campus bookstore. In those cases, the bookstore will purchase the codes from Packback at $25 per code and determine the selling price themselves. Packback does not have any influence on the selling price at the bookstore level. Because of that, you might notice the markup when buying a Packback code through your bookstore.