What is the best way to get discount tickets for the Broadway shows that come to San Francisco on tour?

I’m interested in seeing Wicked at the Orpheum theater in San Francisco, and would also like to find other ways to get discounted tickets to theater in SF. I tried Goldstar, but they didn’t have the dates I wanted and the tickets were still pretty expensive ($50 each). Any other ideas? Is there a discount last-minute ticket booth here similar to the TKTS booth in NYC? Or are there discount services you can sign up for ?