I love ballet and I'm not scared to admit it. Their operas are also excellent.
If you want to save some dough, arrive there the morning you want to see a show ( so around 9:30-10) to buy 'rush tickets'. These are usually half off.
If you're will to watch a show standing up, you can snag up standing 'seats' for $12 (which is what I always do). Caution, each show is usually 2.5 - 3 hours including intermissions.
Standing is better for your health than sitting so do your body and your wallet a favour and stand ;)