Hello Jar Jar, it's so good to hear from you! Unfortunately I don't think I have many useful tips on this specific topic, as my experiences buying textbooks date to the late 2000s (you used Amazon or AbeBooks back then, because at the time those websites were not secretly the same website nor as obviously evil). Grad school is more recent, but as a literature PhD that's mainly just buying novels and such, and the economics of that are way different from textbooks. I also cannot begin to guess how Canada impacts any of this. But if anyone reading has some pointers, I'm putting out an open call here to let us know in the comments!
Also, Jar Jar, if you're still in school I imagine your Senate years are ahead of you, so please take seriously this advice for the future: Sheev might seem nice but he is not your friend.
Hello, Jar Jar! I just wanted to add that depending on where you live & are attending school, you might have good luck getting most or even all of your textbooks from outgoing/graduated students from your program via Craigslist or Facebook Marketplace! If you belong to any student groups on Facebook those can also be a good resource for cheap textbooks.
Best of luck, Jar Jar! Loved your plate stunts in that one banking clan episode