All about hobbies

What do you call experience that was gained from a hobby or professional association?

Is it still called professional experience even if you werent paid or hired to do the skill? What if it was a hobby that earned a little money such as selling and trading collectibles? It was not a liveable wage, just enough money to fund the hobby.
I am trying to complete a resume and want to include the skills learned from scouting, collecting and selling used rare and collectible books. Im just not sure if you can include those skills under the heading of Professional Skills unless you were paid/hired to do it.