I sell multiple DRM free illustrated editions with different illustrations. At a very affordable price like a three bucks or less.
Spend some time at deviant art, and other art sites.
There are (and arguably have always been) More artists of decent ability than there are art buyers. Resulting in a lot of good work that is either not done for pay, or done for very low pay. The same is true of musicians, and writing in general.
So I would hold illustration contests periodically, rewrite the post script to tell about the different artists, and see If I couldn't sell multiple copies of my work.
This model (with adjustments for using public domain or affordable classic art) has been the standard model for selling poetry since before I was born. I believe this old horse has quite a few races left, and I am in favor of recycling the idea.