(Just a quick post as I'm coming back from an amazing event and am still in the catch-up mode of it all and I'm putting finishing touches on my own event.)
It's no secret that I buy the majority of my costumes or now I've actually started to have them made custom for me. Here's my rationale for purchasing: they know what they are doing so it takes them less time and will yield better results.
See, I'm good at sewing but I'm good enough to get me into trouble and have a general idea of how to do things but not enough to fully pull it off for it to look professional enough. Truth is, if I didn't have a day job, I could probably do a better job at costuming than I do. But I happen to have a day job. And we can really say that belly dance is a second job for me. I do spend a minimum of 7 hours in the studio each week teaching. And then I need to spend a bit of time on my own personal practice. And I have gigs or events. And I have to sleep. And spend time with the husband. Heck, there are some friends who I barely see because I'm so busy! So if we add costuming to the list of things that I have to do, I quite frankly don't have time to do as good a job as I'd like to.
So instead of having a subpar costume, I purchase my pieces. There are a number of very talented ladies who will do a better job and do it faster than I could. So, sure, on the surface, it would cost less if I made it myself... but that's when you count the cost of materials only. Add in the amount of time that it would take you to do it and consider giving yourself minimum wage for those hours. It doesn't take long for you to figure out that item X that seems pricey is actually reasonably priced.
AND the amount of time that I'd be spending on costuming is actually time that I wouldn't spend on my own dance. I fully take to heart Asharah's advice about it's better to be a well rounded dancer than having a ton of costumes. That goes in the knowledge vs. trinket mindset for choosing how to spend your money as well as how to spend your time. If a costume would take me even a meager 10 hours to do (in costume time, that's not a lot), then that's 10 hours that I can't spend dancing and honing my skills... or resting. Because you do need rest. Also, chances are, what would take me 10 hours, might take 5 hours (or less) to someone who is more skilled at costuming than I am.
See the math?
Now, obviously, purchased costumes are not free... but there are ways to maximize the investments. Sets are great but if it's something that can only be worn together, then you have one costume. If you have a bra and a belt that can be worn with other items, then you have more than one costume options in your stash. It's really kind of like most advice on work wardrobe: buy separates that can be worn with other stuff.
Also, beware of the "OMG! This is awesome!" effect. So you're madly in love with a piece but it's pricey. Think about it for a minute and analyze whether it would work with what you have or where your dancing is going. If the items are nice but you'd need a whole new everything with it, it may not be worth investing (unless you are looking into investing). If your style is fusion but the item is screaming cabaret, it may not be what you want (unless, of course, you're going cabaret). And think about whether it's too similar to something that you already have. I've been guilty of essentially buying very similar items in the past because, well, I liked them... which is a duh! moment. Think of the color schemes that you have and those that you do not have but maybe want to branch out towards.
So, before embarking on a costume making endeavor, ask yourself where your time will be better spent: making the costume or dancing? And be honest about the amount of time it would take you to make the item(s). Some items are worth your time like a simple skirt or simple pantaloons. But, for other items, it may not be so. If you do decide to do the costume, start it early enough so that you don't have to be sewing the day of the performance. So, yes, this would require planning ahead of time.
And remember: you can always resell the items that you purchase. Of course you won't get the full price but the items can be resold to a portion of the price and be enjoyed by someone else... thus giving you money to re-invest in more costuming.
I think that it's only fair that I tell you where I get my more unique stuff.
Tombo Studio, featuring Anaar's amazing skills: http://www.tombostudio.com/
Note that she has an Etsy store. She made an overskirt for me as well as my (now) infamous bra with feathers and metal wings. And she's making me something new that will make its debut very soon.
Geisha Moth: http://www.facebook.com/pages/Geisha-Moth/101129349421
She makes all kinds of lovely items in limited quantity per fabric. She definitely caters to all shapes and sizes. Purchasing can be done through Etsy, flashes, and wherever she vends. And I gotta say that a lot of her stuff (pants, skirts, cake capris), I end up wearing outside of dance a lot.
Yasemin Yildiz: http://www.tribalbazaar.com/yayicubraand.html
She makes awesome bras, belts, skirts, arm thingies, head thingies, and all kinds of shiny thingies. Her items are always attention-grabbers and properly shiny for stage.
Red Camel: http://www.redcamel.net/
Not costuming per se but where I buy most of my jewelry. You can find DIY items there and on the Tribal Bazaar site as well.