No way. Whoever said 100 to 900 is fine. If it is for entertainment in your free time. Just playing it for fun.

That might work. If it is a hobby. That electronic keyboard worth a few hundred yuan may polish off your hobby. Generally, the feel and sound quality of those priced below 500 yuan are very poor. It can only be called a children's toy piano. The feel and tone of around 700 to 1000 won't be bad. Can be used for home entertainment. For example, some low-end pianos from CASIO and domestically produced pianos. Yin Fei and the like.

In terms of adult learning. Generally not recommended for less than 1,000 yuan. If you don't want to spend too much money. Also buy something over 1500. Only such a piano can be called a musical instrument. In musical instrument stores, instruments priced around 1,500 can only be called entry-level low-end instruments. Generally, the mid- to low-end ones are around 1,500 to 3,500. Mid-range ones range from 4,000 to 8,000. High-end ones generally cost more than 10,000 yuan. This is just a vague division. Not necessarily accurate. That's probably it.

What I recommend is YAMAHA’s PSA series. If you like to play pure music. If you prefer piano music, buy an electric piano or the DGX series. If it is music, arrangement or accompaniment, then the PSR series is suitable.

I'm just going to give you a preliminary explanation. If you really want to buy it. Check out relevant websites.

It is recommended not to buy anything below 1,000 yuan. That can't be called a musical instrument.