Go to J&R music downtown.
I was there yesterday, and they have some pretty insane sales. Of course, all the new releases are between $12.99 and $14.99, but there are some older shows on sale for $5.99.
Things like WEST SIDE STORY, COMPANY, ON THE TWENTIETY CENTURY, A TREEE GROWS IN BROOKLYN, IRMA LA DOUCE, etc. There are literally dozens of great shows for literally nothing.
Just a heads up - I don't know how long it lasts, as J&R's sales seem to be constantly changing.
"If you are going to do something, do it well. And leave something witchy."
-Charlie Manson