Materials
Silk, 19.99/yard. Satin, 10.99/yard. Broadcloth, 3.99/yard. The Choice is Yours
There are a lot of things to consider when choosing a material for a cosplay, whether it be for the entire thing, a prop, or just a small accessory. Yes, duct tape WILL get it's own mention.
Chocobu
Dear god, if you have a joanns around you and you plan on sewing your cosplay, use the sales. It might take a couple trips to get all your fabric at a sale price but it is especially worth it when having to get a lot of fabric and a lot of different types of fabric for a particular cosplay. These sales alone saved me about 20 dollars on a costume and let me upgrade to a more expensive fabric at the price of a cheaper one.
On the topic of fabric stores, be sure to check out the leftover bin. You can get great deals there, and sometimes it really is just the material you're looking for. However, remember that having a good material will serve you better than just the cheapest thing you can find. Your costume should have some longevity, after all.
Chocobu
Another thing I am guilty of is using costume satin when it isn't called for. If the costume requires some sort of shine to it, try not to use costume satin (I've heard it looks rather cheap). Maybe upgrade to the next higher priced.
A tip for materials: It's easier to buy a jacket from the thrift store and alter it to match your character than to sew an entire jacket. It can also save you money, because you won't need to buy the cloth, just some thread and such (personal example, my
Gojyo cosplay I purchased the jacket at a thrift store. It's made of suede. I hid a front pocket, rearranged some buttons, and added the black collar liner to it. Total cost? $5 for the jacket, $0.50 for the felt, $0.99 for the thread. To make one would have been much, much more than that.)
Tsuki Sune-ku
Don't forget! Thrift stores are your friend! Just pick up some items, do a little altering if necessary, and you can have a pretty good costume. My sister's Cinderella outfit was mostly altered thrift store finds and the end result was
this(if you haven't seen it yet). We made the bandana and apron out of leftover broadcloth too.
Pretty much the same thing with my Malin cosplay, except a good portion of that was Wal*Mart finds. Still cheap clothes.
And just as a side on on the whole satin thing- If you're going to use satin, use the stuff that is meant for prom and formal dresses. It's about $8/yd, so use your coupons. It's so nice and Casa Collection is pretty good quality. I'm guilty of using it in my costumes.
Trompe
And as you said about Thrift stores, it's so true! I found many a good piece of clothing/shoes/accessories that after a tiny alteration, looked awesome at half the cost of one online or such~
Like i said, Duct Tape gets it's own special mention.
My friend has used duct tape on every part of her costume to date. She made Lavi's hammer (a small version) out of a sock, a pencil, and duct tape. The leg holster on Lavi's pants was also made of duct tape.
Duct Tape is great because it comes in a lot of colors, or you can color it with a marker. It's easy to work with, and... yeah. It's just great. Plus, of course, it's cheap. ^-^
Atari-555
Sometimes a great way to keep the cost down on your cosplay is to simply be creative! Take my cosplay in my sig as an example. This is me dressed as Fran from Final Fantasy XII. Does it LOOK cheap?
It seems to surprise EVERYONE that I only spent around $6o dollars on it!
The materials that you choose can make or break you. I made all of my armor out of craft foam-- super cheap and super easy. The body suit was a leotard that I bought at a Wal-mart, cut up and hemmed. The ears were made of coathangers and rabbit fur.
Seriously, Just be creative and you'd be surpised what you can do!
Gennivieve
Since most of the posts here are talking about plainclothes costumes, or things that are reasonably close, I would like to take a moment to say you
can do some of those wildly fantastic costumes on a budget.. if you have a lot of time.
Patience and planning is really key. If you're one of those people who likes to wait till the last minute, then this won't help you at all, however if you can plan ahead, you can work things out.
Basically saying, you can collect materials over time. Joanns has had a lot of 50% coupons out lately. I like to go and get material while it's cheap, for future costumes. Thrift stores are great (as people have said) not only for pieces you can alter, but also for material in general. When I need smaller pieces of leather or denim or something, I go to the thrift store and see if they have anything made of what I need. Usually it's much cheaper to hack one of those up than it is to buy the material itself.
If you're looking to make armor or something, don't scoff at cardboard. It might take some trial and error the first few times you try it, but you
can make cardboard look good.
Improvise! Sometimes what you need might be to expensive for your budget. Look into alternatives. Get creative! I can't tell you how impressed I am with people who come up with solutions I probably never would have thought of, and make it look good.
Goddess of Manga
When it comes to getting anying at a craft store (I use Michaels) look for coupons. They usualy come out once a week and work only for a period of two or three days but they are worth it. Some are 50% off any item so it you space out buying items you save alot of money.