[newbie] lights control & ask for some more docs

I’m completely new to domotica, and I have some basic questions, in particular: what hardware should I buy/build to control my home lights? I did’t find anything as such in the documentation, on www.home-assistant.io, is there?
My house is full of old, traditional, light buttons, how can I control them using this software?

The following, for example, is an interesting discussion, I would like to find similar subjects in the docs:

Thank you!

No one is really going to tell you what to buy. Its all going to be up to the person and the situation. If you’re in an older house where the wiring may not include neutral wiring then that limits some of your choices. If you want simple and easy look at a hubs and lights like the phillips hue ecosystem. If your house contains neutral wiring you could go with MQTT or ZWave switches which could be a better, cheaper option for a whole room.

If you have the skills to build your own stuff then things like ESP controlled devices are a fun thing to do.

Again, its all about what you can get your hands on, what works with your existing hardware, and lets be honest, how much money you want to spend.

Thank you very much for your suggestions.

One more little question.
Why this
costs 4$, while this
costs 20$ ?

I cannot get the point.

Oh, and this
costs 72$.

For the same reason all cars/homes/toasters/phones/books/hotels/etc don’t cost the same price.

Long-term support
Evolutionary path
Standards-based vs proprietary protocols

Ok, of course. But could you be a little more specific? In that specific case, which specific features make one product better than the other one? In your list, I am interested in particular in “Features” and “Standards-based vs proprietary protocols”.

The one best suited to your needs depends on your requirements.

My requirements aren’t fulfilled by any of them; the lights I chose use UPB technology. They cost even more than the zwave light you mentioned (but cheaper than Lutron’s Radio Ra 2).