Most fan art is in poster format, so that people can purchase it, and hang it on their wall. It's usually done in a semi-professional manner, so people get the opportunity to get a unique take on their favorite characters. So if you dig Batman, you can come to a convention and purchase unique posters featuring Batman. The image above is an example of a fan art of Batman that I did years ago that I still sell today. The image is printed on glossy 11x17 poster board, and is absolutely beautiful to look at. People love it, and I've sold over a hundred of these posters since I started selling it in 2011. Its netted me a pretty nice amount of money over the years, and is a vital part of my table product.
Fan art serves several purposes for the inspiring artist;
1.It drives people to your table.
2.It shows that you can draw popular characters.
3.It makes you look like a more serious/legitimate comic artist.
That last part is a point that a lot of people miss. The bizarre thing about the comic industry is that people don't really think you're a "real artist" unless you can show that you can draw popular characters. I've been at shows where people have the most beautiful original character artwork imaginable, yet get completely passed by as a kid runs over to buy a poorly drawn image of Dragon Ball Z. People have actually asked me if I draw for Marvel of DC because of the fan art at my table. Being able to draw popular characters well, and even to the point of rivaling the professionals, adds an air of legitimacy to my work. Through that legitimacy, people commission you to draw original artworks featuring more popular characters that can in turn net you even more money.
However, it should be noted that there is always a place for your original stuff at your table. There was a period where I wouldn't have any Psychic Soldier Kai work at my table, simply because I was doing nothing but fan art (and its a big reason why there's been a 3 year gap between PSK 3 and PSK 4). I'm proud to say that when I return to conventions either later this year or next year, you will always find PSK material at my table. Why? Because while people want to see and purchase fan art, they also want to see your original work as well.
So my suggestion would be to do both; Do great fan art to draw people in, and do great original work so that people will purchase your property. As fan art grows in popularity at comic conventions, your original work will help you stand out from a crowd. With that said, if you're going to a comic convention, make sure you're armed with great fan art in order to earn as much money as possible. Those convention tables are NOT cheap.
