Buy one (3 on sale)
Initially sold for ¥31,400
If Yamaha's naming scheme for Portatone ever made any sense, the Yamaha PSR6 should be the lowest tier of keyboards available alongside the PSR16 and PSR36 in 1988. It was then replaced by the PSR7 the following year.
It's very similar to the Yamaha Portasound PSS170 or PSS270, but it has 49 full size keys along with a mono speaker on the left. 100 sounds and 10 rhythms, melody sequencer and auto chords.