I’m currently in college in the Southeast. My freshman roommate and I decorated with some wall stickers, fairy lights, and posters from the poster sale. Nothing extravagant, but enough to make it cozy. My XL Twin Target sheets matched.
I’m now living off campus with a group of roommates from the same building. We each have a few posters in our bedrooms, more of our own (IKEA) furniture, and have decorated our common area with a poster wall. Nothing expensive or extravagant, but something to make it ours.