What are best way to buy crypto?

I was wondering that for crypto to stay decentralised it needs to be available to bought in decentralised way with fiat for anyone who needs to add more funds . Here are some that i think cam be marked. 1. OTC/P2P 2. EARN CRYPTO SALARY RATHER FIAT 3. BY MINING / RUNNING NODE ( ONE MAY EARN VIA IT BUT IT CAN BE VERY EXPENSIVE) PLEASE ADD IF YOU KNOW ANY MORE WAYS (PS- ANY IDEA THAT YOU THINK CAN PREVAIL IN FUTURE IS APPRECIATED)