Why would that make us angry?
Anyway, no, you don't have to buy a costume with it. That would be a little silly to wear everyday to school/work/whatever, wouldn't it? You're fine just getting a wig.
As for class caps, I have no idea.
Tsumugi Kotobuki - Waitress Ver. [ K-ON! ] - 100%
Yuki Nagato - Disappearance Ver. [ The Disappearance of Haruhi Suzumiya ] - 100%
Lara Croft - Reboot Ver. [ Tomb Raider ] - 90%
Kyouko Sakura - Casual Ver. [ Puella Magi Madoka Magica ] - 100%
Makoto Sawatari [ Kanon ] - 100%
Charlotte - Human Ver. [ Puella Magi Madoka Magica ] - 40%
Ayu Tsukimiya [ Kanon ] - 10%