As my resources are quite limited, I’m rather dissatisfied with the choice I have. I just see that Yamaha has such a keyboard as PSR-EW410, with 76 keys, quite lightweight and affordable, and it takes only giving it a decent polyphony and few more decent piano and epiano voices (which Yamaha has) to make it suitable for professional usage, but Yamaha protects their sales of more (much more) expensive equipment.

You can say that it’s not a perfect world, but in areas where competition is much harder, the world seems more perfect – computers, phones, cameras – you can buy them on your pocket money now, but keyboards, even used ones, seem to be as expensive as they’ve always been.

I'd say, when it comes to keyboards, we have Apple, but we still don't have Android.