Are you under 35 and who are you going with? There may be cheaper alternatives for the Broadway shows so you can do both AND see Julie Andrews. Not sure what price range you are looking to stay in.
Lincoln Center has LincTix (
http://www.lct.org/linctix) for 21 to 35 year olds. You can only get 1 ticket per person, but it says you can coordinate with other members (you can get your companion(s) to join if they meet requirements) to see shows together.
There is also HipTix via Roundabout that offers $25 seats, but they are in the mezzanine. If you upgrade to HipTix Gold ($75/year), you can access orchestra seats for $25. You can buy a max of two tickets. Might be worth it if you are interested in other Roundabout shows down the road:
http://www.roundabouttheatre.org/Shows-Events/HipTix.aspx Enjoy your shows!
"We like to snark around here. Sometimes we actually talk about theater...but we try not to let that get in our way." - dramamama611