The newspaper used to cost money.
I'd buy the Independent for my train ride to London. Back in the early 2000s I guess it was about a pound. Every day I'd spend a pound to read the news.
Hundreds of thousands of people would do the same. That money went to the newspaper, who used it to sustain their business; to pay their rent.
And to pay the journalists that wrote all the content. Who then used that money to pay their rent, and to eat.
Doesn't seem _that_ difficult a concept to grasp?