Where should I buy my cosplay costume? - Alice from Pandora Hearts?

Ok so I want to cosplay as Alice from Pandora Hearts since I like her character and we are very much alike. Thing is I need a good, reliable websites that sells the wig, shoes, and costume for Alice (they can be from different websites - I just want to get a good price for the item and it to be good quality). I have time as the con I want to go to is sorta far away in time (I am planning to go with friends).

Um and if you could suggest anything or give me some helpful hints for going to a con (its my first time going to a con but I know that this con is POPULAR so its gonna be hectic).

If I remember anything that I forgot to mention or I suddenly remember something that may be important, I'll post it.

Thank you for helping me! Oh and I know some people will think this so I will say this now - I am not trying to get others to do the research for me ( sorry if it seems like that). It's just that I am really busy with school and have so many freaking projects I don't have much time to do deep research. But I have been doing SOME research during some of my classes but I have this feeling that I am missing or skipping some good website and I would just like to cross-reference with someone. Thank you again (for helping me and reading this long and pointless explaination)!