I used to color comics professionally. When I started out, I was like most young, brand new freelancers: I had no idea what I was doing and signed on with a shady company. They paid me very little but kept giving me loads of work.
Eventually, they asked me to do a bunch of lettering work for $1/page. After a few projects, I convinced them to up it to $2/page.
After working with them for about a year (when I had started to wise up to this being a shady deal), they asked me to draw, color and letter a whole project for about $20/page. They only asked if I could draw, without ever asking to see the extent of my skills.
They never asked for my character designs, sketches, or updates. They just wanted me to hand in the finished inks before coloring them. So I set myself a time limit on each page that would make the fee at least marginally reasonable.
Ultimately, they were pissed at the quality of work I turned in, and I have never been so happy to be “let go” by a company.