You don't have to go too crazy for your first costume. As far as buying two pants/shirts: It would be best for you to keep to the same exact style/color so people could recognize you were out as the same character (as you may be in a different costume coming out during your cast shift). It's a good idea to have two sets of the same costume though, especially in the hot months when you're overly hot and sweaty and want to change into drier clothes.
Realms of AdventureLive The Magic!