To be honest I doubt the PT-30 is really worth any more than $25 euros so you a probably overpaying for it. It is a very early Casio with monophonic ( one note at a time ) output but it does have accompaniment features as well.

But to be fair it seems people do enjoy their PT30 ( see http://reviews.harmony-central.com/reviews/Keyboard+And+MIDI/product/Casio/PT-30/10/1 ) but I really think you could do a lot better for your trade.