I sell the Casio WK3000 for $299.00 including the AC adapter and stand.
I have a couple of refirbished WK3000 keyboards (from the factory in clearly marked boxes) for $229.00.
The WK3500 sells for $399.00. It offer seperate stereo outputs rather than just a headphone jack to go line out. The WK3000 only has a headphone jack in the front to use as line outputs. Using headphone jack turns off the internal speakers when using an external system but not with the WK3500.
The other two differences would be the floppy drive on the WK3500 and the modulation wheel on the WK3500 instead of a modulation button on the WK3000.


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George Kaye
Kaye's Music Scene
Reseda, California