How good for 600?

I have $600 to spend on a keyboard. I want an 88 key keyboard too and has a good piano sound. I'm doing a show around christmas and I pretty much need a portable piano, so I figured I should buy a nice keyboard with 88 keys. Thanks in advance.

Important question before attempting to answer.
Would you consider purchasing used (not retail) equipment?
MORPH!

I managed to find a used (but well babied) Korg SP100. $600 Can., so U.S prices should be much lower. She suits my purposes just fine.
Good Luck in Your Search

Where can I find these keyboards at?

Get off the computer and start looking in the newspaper. Less chance of getting ripped off as with ebay!!!