This website is a must! The Prop Store. They sell authentic used movie props and costumes. You could build or add to a costume you already have with real movie items. They have a really cool auction going on right now for a movie called Seventh Son - with costumes and props worn/used by Jeff Bridges, Julianne Moore and Game of Thrones hottie Kit Harington! I've included a couple of really cool costumes below. Seventh Son Auction So Many cool things in this auction. They have tons of stuff from other movies too. Check it out.