There are some snakes that can be bred for profit. Think about it if it was easy every one would be doing it. Many snakes loose their value as they get larger. Every one wants a baby. Most zoos have more than enough snakes, and won't take one even for free.
Snakes are like any other living creatures.
They require care. So you still want a snake, hit your local library or bookstore and start reading. Call a local collage or university to see if there is a Herp Club in your area. Meet some other people. Than go and find the one that is right for you.