The other trick if you've only got one brush (a baby kabuki is best for this) is to wipe off the minerals on a microfibre cloth after each application. Like when you finish your foundation, wipe off the brush on the microfibre and that will get most of the colour off the brush, then you can do your blush, etc.
Also, there's a nice synthetic set at
Silk Naturals for $21. The powder brush is equal to a baby kabuki, there's a nice blush brush, an eyeshadow crease brush, a push brush for liner or detail work, a spoolie, and another couple of small brushes that you can use for concealer, eye shadow or a lip brush. It's the same set that FF sells, but cheaper, and it's good quality - I have two sets. You can do your entire face with it, and it's really not a bad deal at all.