Make a group booking
Most venues offer discounts group bookings, many for groups as low as eight. That's, like, what? Four couples? Two families? One book club? Easy. Frozen the Musical even has a pretty outrageous group booking deal for groups of just four.
This is especially useful for those big musicals at the top end of town. Ticketek and Ticketmaster have their own group bookings department where you can expect to save between $5 and $20 per ticket depending on the promoter. The advantage of a group discount is you won't get stuck in seat ZZ 99 for the sake of saving a few bucks. Just the opposite: you might end up with a few perks thrown in.