I would absolutely not try to publicly sell your finished work!
I'm saying this for your own safety. The images are very much so copyright protected and can carry a very stiff fine, imprisonment or more!
I always like to put the shoe on the other foot. By that i mean this, let's say you created an original character...oh, like Mickey Mouse for example. Yep, the world loved your creation and it was in movies, books etc...a very well known character indeed.
I after seeing your Mickey Mouse decided thaty I too would like to make lot's of money by using (stealing) your character's image and put it on lunch boxes my own book and other items. I realise that you are not trying to pretend that you invented this character. How can i put it? It's basically trying to take a ride on the coat tail of someone elses success.
The company can sue you big time for it and quite often does just that...especially Disney characters.
Why then do people continue to sell stuff with well known characters?
They just haven't been caught yet, by either the company that invented the character or Ebay or both.
I've done painting of famous characters too but saved them for my own collection or given them to family or very close friends. I've posted their images on my web site merely to show folks that I am capable of doing the work, but these particular items are in no way for sale!
I'm just trying to save you a bunch of grief and lawyers fees
If you are going to privately sell it and keep it out of the public eye then you may be able to get away with it. Just be sure you know who you are trying to sell it to.
Let your conscience be your guide!