I got mine the first time through QVC as a "Try Me" special. Since then, I've bought refills at Sephora.
O.K., now I know we have a lot of BE fans here, and I love it too, but I just bought something that seems to be just as good for about 1/3 the price.
It's Physician's Formula Mineral Wear Loose Powder. CVS sent me a coupon for 20% off any cosmetic, so I used it to try this. And it's great. A bit messier because of the packaging, and I'm not crazy about the brush that comes with it. However, I'm using my BE brush with it, and the coverage is just as good.
Applying mineral make-up correctly is the key, I think, to how well it works. You have to start with a small amount of powder, worked well into the brush, and apply it to the cheeks first, fanning out to the nose, chin and forehead. You need to layer it a small amount at time and buff it enough too.
The instructions that come with BE are very helpful, so maybe it's better to start with BE? (I noticed that Neutrogena is also selling a mineral make-up now too.) I've been using it for a couple of years now, so I'm used to applying it.
One last comment--I have also tried Sheer Cover (the one Leeza Gibbons touts on an infomercial). I was as happy with it as I was with BE, and now with Physician's Formula. I suppose there are formulation differences between the brands, but all of them have performed fine for me.
Good luck!