Bully

This achievement requires you to purchase 100 cans of soda. The fatest way to do this is to go to the Yum Yum Market after Chapter 1 and buy 100 cans of soda all at once. This way you won't have to watch the drinking animation every time you buy one from a vending machine.

This requires buying 100 cans of soda, at machines or in shops, cans picked up after beating enemies won't count. I kept stopping at the one in boys dorm and by school door and buying a few every time I passed.