I wouldn't say she has millions of shoes, but I've seen her with at least four, those being her house slippers, her shoes she wears for casual wear, her tennis shoes for P.E., and her school shoes. In episode 44, she's shown changing her shoes in the front door, so that's probably where she keeps her casual shoes and house slippers. In episode one, they show Sakura changing into her school shoes in front of her locker, so she probably keeps her school shoes there, and since we only see her wearing her tennis shoes when she's doing sports, she probably keeps those in her locker as well. One thing I've always wondered about is does every student at Tomoeda walk or ride their bike to school? You always see people walking or bike riding to school but other than Tomoyo, you never see anyone ride in a car to school. Do they even have school buses at Tomoeda Elementary? What if you live too far away to walk to school and you don't have anyone who can drive you there?