I love love love Halloween! and yes if you go to those stores you will just get the cheapy mass produced stuff. You gotta be a bit creative when you want to be unique! Me and my bf are doing gypsy pirates this year. We have been collecting vintage jewelry from various countries through the year. But I also love period costumes too. Go to a thrift store and you can do 20s, 40s, 60s, 80s, etc. Personally I love the 70s, 1870s that is!
Or how about
:
king and queen
famous celeb couple
characters from your fave movie
doctor and nurse (it's cheap!)
magician and his assistant (I've always wanted to do this one)
Cleopatra and Marc antony
Dracula and bride
these are just off the top of my head. Hope I helped a little!