$100/week seems a lot to spend on personal, when the school feeds you, there are free events on campus. Maybe that poster meant per month.
OP, some on CC think rich kid things dominate on campus- going on regular shopping sprees, dining out, theater and concerts, etc. Not.
Mine focused on on-campus things, that Friday film at the student center, hanging with friends, heading for class or the library together. Many dorms have some group watching a sports game together in a common room. If your friends want to order pizza, your share is a few dollars. (But mine didn’t even do this as freshmen. And their mega wealthy friends were right there with them, in the dining hall or at the free movie.)
So many choices.