I believe in many ways, we have been getting off very lightly in this field of interest. The price of Broadway memrobilia is peanuts compared to that of motion picture collectibles.
I can still buy stuff online for less than 20 bucks. Try buying ANYTHING film-related from Heritage Galleries or Profiles in History for that price. There is a finite amount of Broadway treasures out there - far fewer copies of individual items from the 30s and 40s and even the 50s than Hollywood collectibles. The prices are going to go up as people discover this as a growth market. Sure, it sucks, but that's life.
On the other hand, my collection of Fred Astaire opening night programs (I have every one except "The Bunch and Judy") has gone from the ten-or-twenty dollars I paid for each to many hundreds
each when I last had the collection appraised.
http://www.broadwayworld.com/board/readmessage.cfm?thread=972787#3631451
http://www.broadwayworld.com/board/readmessage.cfm?thread=963561#3533883
http://www.broadwayworld.com/board/readmessage.cfm?thread=955158#3440952
http://www.broadwayworld.com/board/readmessage.cfm?thread=954269#3427915
http://www.broadwayworld.com/board/readmessage.cfm?thread=955012#3441622
http://www.broadwayworld.com/board/readmessage.cfm?thread=954344#3428699