Try the Marketplace. It has tons of premade costumes and lots of people that will gladly take costume commissions.
"Katsu, every time I see your avatar I automatically think, 'Wow, she's really annoyed today!'"
Done | Red Mage Viera
In Progress | Vault 34 Jumpsuit | Sniper Wolf
Planned | Catwoman | Snow White
Cons | ALA | AOD | Cherry Blossom Festival | Fanime