I’m going back and forth between posting this or not: here’s my dilemna, all of my firsthand experience is with modeling and a little acting, not with music. On the one hand, the behind-the-scenes business part is not that different, on the other hand, it kind of is. So take this for what you will:
You might want to look into getting an agent. I don’t think you’ll need a manager until you’re really really busy. Look into some local talent agencies. Just google your city’s name and the phrase “talent agency”. They generally take 15% of what you make, but they also get you a lot of gigs. They know everything that you need to know, and they can help you be the most successful artist that you can be.
Financial relationships with managers are a lot more varied than with agents, but they typically take 15% as well.
I’ve never had a manager, but being with a talent agency, the only out of pocket expenses I was ever asked were webmaster’s fees to put my info and headshots on their website. It was $50, which I thought was pretty high at the time, but who knows.
One sure sign that an organization is fake is if they want a lot of money from you up-front, so beware of that. No agent or manager should ever ask you for more than that.