Discount codes/websites for April trip

Planning a trip to NY at the start of April and hoping to see some shows. Was wondering if anyone knows of any discount codes or good discount websites for getting tickets. Don't really want to take the chance on rush tickets etc as i am a planner and only have a limited number of days there!

At the moment the shortlist is Mean Girls, The Bands Visit, Beautiful, Come From Away. Also seeing Frozen but tickets booked for those already. Thoughts on any other shows i should consider or opinions on these also welcome!! Can probably see two of my shortlist (possibly three at a push).

Check out BroadwayBox, which has official discounts for shows (typically the same as you'd find in e-blasts and direct-mailers). Beautiful will likely be on TKTS (and maybe others, too) of you want to try to save a little money.