In addition to artists selling prints and originals, I've been buying (or have been gifted) tote bags, coffee cups, a wallet, Tarot cards, etc., with the designs being fan art, through Redbubble, Etsy, a Canadian site whose name I've forgotten, etc., etc. And of course there's the new(ish)? thing of "tip jars", a concept that was very new to me. I've used given a tip to a fan writer who is a particular favorite of mine through one of these sites. (I can't remember the name of the site now, but it had something to do with coffee.)
Everything's truly always a moving target. My definition of the only thing that truly defines fandom - any kind - is the passionate active engagement of the fan with the subject.