It always depends.
I can only say, that the artist I found for my comic, I know for a while now.
I can only tell you, look for an artist that might have the art that is fitting for your story, and ask if they do commission work. The commission 2-3 artworks, to see if they are after your liking and if they had fun drawing them. Ask if they are interested in working with you and show them a script.
About the money, we were able to agree on a fund system, where I load it up, and the artist is using it until it's empty. But be prepared to have some money left, and don´t expect people to pay you for it. And never see it as a job, just as a fun project, that might get somewhere 