If you have a talent for art, whether drawing, painting, or anything creative, there will come a time when someone asks you to do something for them. It's at that moment that your commercial art career begins. Mine started in high school. Your starts anytime you begin to work on assignment.
It always goes like this: Someone sees a drawing that you did of a dog, for example, and asks if you can draw them a drawing of their dog. It's at this point that have to begin negotiations. That is, you have to ask yourself "why should I go to all of that trouble for this other person?" But before you jump to the conclusion that you are being selfish and greedy, consider the feelings of the other person. They have asked you for something and don't want to be selfish and greedy themselves. If you insist on getting nothing, it would be very difficult for them to look at the nice drawing that you did, nod and just walk away with it. You might say, "well, a thank you would have been nice". And people do want to show their appreciation, many times with money, or lunch, or something tangible. This is the beginning of making money from your art.
I started drawing cartoons of my friends in school in exchange for their smile. I derived enjoyment from seeing their enjoyment, and hearing their appreciation. I kept doing this by volunteering to do artwork for the high school yearbook, and this time I was "paid" by getting the art supplies I needed. I got to draw on premium board, I got to use expensive "tinta china" and used a great assortment of pen nibs. I wasn't making a profit, and that was never my intention, but at least I wasn't having to pay for the art materials myself. If you've done some drawing or painting, you know that the cost of art materials alone is substantial.
I did the same thing for my church. I supplied the artwork and design for posters. I still remember the thrill of a design of mine which had been made into a huge flowing drapery-type of poster that was displayed in the sanctuary.
The most difficult part of making money from your art is accepting the assignment. You have to listen to what your client wants. Remember that dog you were asked to draw? You can't just draw any old dog, it has to be the one requested. I've known a lot of artists who can't stand being "told what to do", and that is the end of their commercial art career.
Personally, I have always liked working on assignment. I started doing it professionally at age 19 when I started my company, then called "Brad Hall Advertising Art" and have gotten so used to it now I don't do much artwork unless someone asks me, and pays me.
By the way, I accept not only Paypal, but Chase QuickPay. See? You can do it, too!