Silk Naturals do great synthetic brushes for very good prices! Also, their delivery is reasonably fast, and their customer service good.
They sell the same brand/quality of brushes as Aubrey Nicole, but cheaper.
I'm totally converted to the premium synthetic brushes, they are really nice and soft, and they don't shed! Application is a bit heavier with them though, but I gather from other threads that you like full coverage, so these brushes may be great for you!
Be careful though, once you start ordering from Silk Naturals, you may not be able to stop, they've got tons of great MMU too!!! LOL! (I absolutely love their foundation and finishing powders, and I've just ordered some lipsticks, lipglosses and eyeshadows too!)