Any advice on how to make a profit off my art?

I've have done tattoo designs for my friends and family. I have also done oil pastel drawings, paintings, and charcoal drawings, as well as other things. People say I am really good and I am wanting to know if I can make any money off of these things. I usually just give them away, but I thought maybe through the internet or etsy? I don't believe that creativity and art really has a price because everything from a child's first scribbles to the Mona Lisa is valuable, but I could just use a little money.