And with me posting that's pretty much all the beatmania fans from this site here.
Yes, the price has gone up on these things in the past few months since people are moving on from DDR into this game.
I just have a couple of 5 key controllers because I'm just a casual player who likes to play 2 players and then 10 key but eventually I'll get a 7 key controller. The way I see it, there's no hurry to get into it when I'm still interested in other bemani.
From time to time people will sell their controllers on
http://www.bemanistyle.com , which is also a good site to check out if you need information or want to chat about the games. As a matter of fact, check out the Cali forum, there's bound to be someone who can help you there.