This site is a big catalog showing a wide selection of halloween merchandise. There are different categories of costumes : capes, clown costumes, classics, famous personalities, pet costumes even plus size costumes.
IF you are looking for masks ,they have them from Hollywood movies, tv and music caracters. To make your costume more believable they offer cream makeup in many colors, fake blood and accessories like wigs, fright fangs, weapons, chainsaws, hands and creepy creatures. If you want to haunt your house they show you unique halloween props and decorations, skulls, jaws, gothic crosses, cows and flying bats, meat market, hands, fingers,heart and ears, coffins, skeletons, candles and candle holders. And for setting a creepy mood: some especial effect including cd, fog machines, voice disguisers, pictures and lights. 
