Some relatives of mine started off their keyboard careers with a really cheap plastic organ with electric (Mains-driven) blower, proper reeds and a bank of chord buttons that gave the basic major and corresponding minor chords. There's a similar toy version on eBay at the moment under the Bontempi name here. Probably similar vintage ('70s?), these basic instruments were probably ousted from the marketplace (and my relatives' home) by the arrival of cheap electronic instruments from Casio, Yamaha, etc. While these were marvels of ingenuity (later models were dumbed down considerably), they never achieved the natural sound of the old reed organ. The cheaper versions available today tend to have miniature keyboards. You might find it worthwhile looking for one with full-size keys, though this obviously extends the overall size (and cost) of the instrument and reduces portability.

I have a Yamaha PSR-195 (this sort of thing) surplus to requirements which might suit, but can't find the power supply at the moment. PM if interested (I'm in Fleetwood, Lancs).

Ross