Is it easy to start a minecraft server?

Yes, you have to pay for a minecraft server unless you want to host it from your pc which is not really the best unless it's just a group of friends.

Yes, you only need some $$ to start off and some good knowledge about plugins and ofc a Brain, but the main problem is your community and other stuff like bot attacks.

follow tutorial in internet and have fun with your friends ) .

You can try but u need to port forward,and that is hard,but try

Its easy to actually start one, A LOT harder to make it a decent thing for the public