I'm sure you can find all sorts of easy-to-make movie costumes around the Internet, but if you aren't afraid of a challenge, you might try tackling one of the more head-turning ensembles listed here (in no particular order).
Satine (designed by Catherine Martin)
How good are you with sequins? You'll need a fair queue of them in order to recreate this glittery garb in which the sultry courtesan makes her auspicious entrance. Start with a simple black corset and start affixing your beads. Depending on your time and resources, you may have to cut corners on the level of detail you include (I'd be impressed by anyone who could adequately mimic the intricate fish scale pattern of the original). Don't forget all the little ornamental touches on the long gloves and top hat. And oh yeah, if you're not a natural redhead, dye it or wig it up.
Alien (designed by H.R. Giger)
You'll have to get creative for this one. Obviously a black unitard is the best choice for a base, but patterning the alien's sinister exoskeleton will require some imaginative dressing. Some flexible black plumbing conduit could go a long way on the legs, arms, ribs, and tail. Shoulder, elbow, and knee pads (custom painted, of course) will flesh out the joints. As for the head piece, I suppose paper maché will work. Molding it may be tough, but perhaps a scoopball scoop could be used to achieve that oblong shape. Use makeup to paint an extra set of jaws around your existing teeth. Bonus points for slime.
Cruella De Vil (designed by Bill Peet and Marc Davis)
You may not believe fur is murder, but I'm sure you'll agree that paying for it sure is (to paraphrase one Julius Hibert). Putting together a realistic yet economical replica of this quintessential cartoon villain's billowing mink coat can be a challenge, but not impossible for a wily costumer. An old bathrobe is a good place to start, with lots of faux fur sewn on loosely to create the illusion of volume. Accessorize with matching purse, red arm-length gloves, green earrings, cigarette holder, and black wig bleached on one side. If you have the makeup know-how, you could try emulating those distinctively pointy cheekbones.
Von Trapp children (designed by Dorothy Jeakins)
Any competent seamstress can assemble these makeshift play clothes. The trick may be in finding sufficiently similar material. Green floral curtains aren't exactly in vogue, but if push comes to shove you can simply cut your own pattern out of a solid shade of green and sew it onto any white fabric. The other trick will be in finding six friends willing to go out in the same duds; the gimmick doesn't really work with only one curtain-clad trick-or-treater. You've gotta have seven. To tie the whole ensemble together, practice the songs! “Do mi mi, mi so so, re fa fa, la ti ti!”
Ghostbusters uniform (designed by Theoni V. Aldredge)
Here's a Halloween standard that's seemingly simple, but in fact deceptively difficult to pull off. The khaki jump suit is the easy part, but if you wanna dress to impress, it's all in the details; making sure you have the all right decals in all the right places, right belts, right boots, even strategically applied wads of marshmallow for added effect. Don't skimp on the back unit either. Simpletons may be content to make do with an ordinary backpack and piece of hose, but I'd go with a Super Soaker backpack blaster which can be easily painted to look like the real thing.
Catwoman (designed by Bob Ringwood and Mary Vogt)
I would never suggest you carve up your own leather finery for the sake of a Halloween costume, so you may have to cheat with your choice of material. If you can get your hands on some inexpensive black vinyl, go for it, so long as it's appropriately form-fitting. The stitching is the important part anyway. Use thick white thread to sew a half stitch pattern along the legs, torso, forearms, neck, and cowl. The cowl may be tricky, but a swim cap is a tight-fitting head piece to which ears and a mask can be attached. Add a whip and detachable claws. Here, kitty kitty kitty...
Dark Helmet (designed by Donfeld)
The beauty of this outfit is that it's less involved than the Darth Vader design on which it's based, and has an even more obscure sci-fi geek appeal! The main body of the suit basically necessitates anything you have that's black and shiny. Upper body hockey pads might be a nice embellishment, treated with a semi-gloss black spray paint, naturally. There's no easy way around the helmet. That's gonna require hard-nosed ingenuity. I've seen some guys work wonders with a salad bowl, welding mask, and plastic garden edging. Finally, you have to devise that, er, oddly phallic neck tie.
Wez (designed by Norma Moriceau)
Look closely at this attire and you'll notice that it's mostly composed of athletic gear: football shoulder pads, jock strap, shin protector (worn on the forearm for some reason), etc. Thus pulling off this look is more a matter of decoration than construction. Feathers, attainable at any arts and crafts shop, are a must around the collar. And a miniature crossbow for the wrist can probably be picked up at any toy store. Note the snazzy stud work around the midsection and belt buckle. Top it all off with a stylin' red-tipped mohawk and you'll be the fiercest road warrior on the block.
Dr. Frank N. Furter (designed by Sue Blane)
If you feel you've got the thighs to go with the garters and fishnets, here's a bold, indelible get-up that's always a crowd-pleaser. You might have a tough time tracking down a front-laced corset though, but you can make one yourself by taking any old black T-shirt and cutting away what you don't need. Less is more when it comes to this costume – except for glitter. Apply ample amounts of it. The makeup is actually the most complicated element of the ensemble. Just remember to paint those eyebrows nice and thick. Best of luck trying to master those bejewelled high heels, fellas.
Scarlet's curtain dress (designed by Walter Plunkett)
Had Costume Design been an category in 1939, you can be sure it would have served to add an additional Oscar to Gone with the Wind's impressive tally of eight. But all of Walter Plunkett's lavish period-inspired threads pale in comparison to this one fantastic gown – the second drapery-derived outfit on this list – fashioned by penniless Scarlet out of Tara's curtains, so that she might convince Rhett that even a destructive civil war can't lower her standards. If Scarlet can do it, then so can you! Any deep green fabric will do (preferably something with a bit of weight to it), and you can make the pull cord by braiding together yellow and green ropes.
For the truly ambitious, try mimicking what Carol Burnett wore in her classic parody.
“I saw it in a window and just couldn't resist.”
