Try what are called "Partial View" seats. For example, for Million Dollar Quartet, seats costing only $38.00 in the orchestra are right next to those costing $126!

Although tickets to some hit shows go for full price, there are lots of discount options available for many Broadway shows. You can get discounted same day tickets at the TKTS booths or at the individual theater box office "rush" lines. If you'd rather buy your tickets in advance, check deal sites like Groupon and Living Social for special offers, and theater sites like Theatermania.com for promo codes.  

NYCCheapTravel.com has a list of current shows with links to "rush" policies, promo codes, and special offers. Discounts list.