My Prana cost $280 (a year ago) and I haven't spent a dime on another mp since, nor wasted a minute playing other mps that are only temporary. Money well spent, I'd say. I like the way it plays, sounds, and looks. What's left? Safari over. New (or old) trumpets that don't work with my Prana are destined for the classifieds. I find it funny that people will happily spend many thousands on the perfect custom trumpet, then complain and moan because their mouthpiece cost more than $50. (what be up with that?)
As for the Monette costing more than other mps .... Why should I care, if I can afford it? (I'll spend more on guitar strings this year) There are probably proprietary secrets of manufacturing them, making so called "copies" a big waste of time, along with hands-on craftsmen hours, that include fine tuning (that other manufacturers can't or don't do). Seems a lot like simple math to me.
The only other type of MP I'd consider at this point is one of Trent Austin's ... word has been really good on them. Again, they're not cheap, but why would a trumpet player want a "cheap" mouthpiece???