I have not been to the Opera House in Zurich, as when I looked at ticket prices even for St. Gallen Opera House (yes, I admit, most of the times last minute) the prices were so high, I supposed in Zurich they have to be double.
What I discovered today (for myself, as it is no secret), is that Zurich´s Opera House offers special “Open Opera Days” for both Ballet and Opera, and those days the tickets are much cheaper (starting at just 16CHF or 50% of the price).
Sounds like a fair deal.
For more info here:
lifeinstgallen 