1) I cosplay for cosplay conventions(Anime Revolution 2012 this August YEAH!)/meet ups. I don't go out randomly in cosplay...
2) It really depends what it is - I'm not gonna spend over $100 on a regular school girl/boy cosplay outfit(Although that would be cheap for a actual uniform lol) but for something like a uniform from Vampire Knight, maybe.
3) Up to $200, and that's with a wig and accessories, but without (a) prop(s). But again, it depends on the quality and detail of it.
4) I prefer exact replicas - but adjustments for different body types is fine.
5) I assume you mean cosplay events outside of Comic and anime conventions - Yes, see next answer lol.
6) As I hail from the Anime side of things, I'd be interested in a anime LARP. If there was one going on nearby, I'd love to join in? lol