Question about buying Webassign access

I'm taking Math 126 this quarter, so I'm trying to figure out how I should buy the required webassign access+ebook. I found [this](https://sites.math.washington.edu/~m125/Registering%20for%20Webassign%20at%20UW.pdf) page which says I can get a discount if I go to [https://math.washington.edu/webassign](https://math.washington.edu/webassign) but when I go to the link it says that I'm "not authorized to view this page", though I'm logged in and registered for the class.

Was this info just outdated or should I wait until the class starts (maybe I can access then?) to buy the access or just buy it from the ubookstore site (or elsewhere if anyone has any suggestions) now?

Thanks in advance, and sorry if this is a dumb question because I missed something really obvious or if this got posted already and I didn't see.