So I really want to start a business but I don't know how to. Does anyone know how to and what business to start for cheap?

Don't. Go to school and take classes in business administration, and in the meantime, try to find work in the area you would like to own a business. You will see first-hand the application of the things you learn in class, and you will also see the mistakes that you learn from so you don't make the same ones. You may also learn useful things that the classes don't teach you.

Many small businesses fail, even when their owners have the education and experience. Going into business with zero preparation, you are doomed to fail.

Prepare a business plan and financial projections and then try bootstrapping finance methods.

If you cannot work that out for yourself then you will never be able to run a successful business.

If someone really knew it, then they would do it.
And if they do do it, then they are competing against you and why would they help you compete against them?