I use a helleberg with the contra I play in our corps, which is a Kanstul Commandant's Own contra although I'm going to buy a pt88+. I would recommend perantucci line for anyone looking for a solid sub $100 mouthpiece as they come in a variety of different mouthpieces.
Just don't do what I tried to at my first corps rehearsal and read in concert pitch, I tried the 2v trick of reading like a BBb horn with third valve stuck down and it was miserable.