I'm not going to talk about the books here. I remember the days (long ago) when I barely got a few bucks back for a $250+ textbook while I completely cashed in on others.
What I am going to talk about the insane variety of Badger gear. And, thus, the insane amount of coin you may drop ensuring that you and every single one of your family members is outfitted in red and white.
The University Book Store is a mecca of everything Bucky. Things that you couldn't even fathom to rep UW are present here. The selection is choice, the quality is high and so are the prices. Do not be shocked to see many a $65+ hoodie. It's the norm.
The kiddo and baby section is especially impressive, so definitely stop by and give a look-see for any budding Badger.
*Pro tip - Bathroom is in the basement (where all those glorious textbooks lie).