Riding sport and Piper both carry some pretty nice show breeches that aren't too pricey. Ariat, Ovation, and Romfh are all very nice too and can usually be found on sale somewhere. All of these breeches are pretty good quality and not priced to badly.
Best wishes this show season,
Kerrits or Horse have some good ones that are really cheap too!
I have elation breeches that I show in. They're pretty cheap but very comfortable and easy to move your legs comfortably