400-500$ range
with sequencer and disk drive

roland xp 50,jv 1000,,korg 01wfd,t 3(no GM)/x 3(ok piano),ensoniq ts 10,yam w7,

no seq

xp30,x 5(too small),
QS series(not recommeded by me)

if you find one let us know,we'll give you more advice.