Good Luck.

Not sure where you live just you might want to check out GUITAR CENTER. They have surprised me more then once with the used keyboards they have in stock. Plus given how large the chain is odds are if they DONT have what your looking for...they can check other locations and get it shipped to thier store ( no cost to you ).

As for price...in general the used keyboards ive seen at Guitar Center are 100$ less or more then the random ebay going prices.