Very Expensive doesn't always mean good. Like I said in a previous post, The Conn Helleberg (120S) is the best mouthpiece out there for middle school-highschool students. I have been using it for a while now, and I am a junior in Highschool.
I wouldn't suggest getting an expensive mouthpiece like Monette or PT yet.
The Conn Helleberg (120S) costs around $50. Relavtivly cheap.
You mean like in school grades? Well you can use anymouthpiece you want for each grade. Mouthpieces last a really long time, I have heard of some being used for 50 years. I personally use 3 different mouthpieces. I use a generic PT (cause I couldn't afford the real thing at the time), mainly for high range, a kelly 18 for outdoors and the Conn helleberg 120-S for normal applications.