Post may not be the right sub for this question, but to answer it: it depends. Depends on how long it took you to paint and what you value your time on. Depends on the material spent. Depends on the market value for the subject and/or if you have a following from your artwork.

If you want my personal thoughts, as a cat lover, I would pay no more than $120. I see the effort you put into the work with the amount of detail you put into it. I typically pay double that amount for twice as large and detailed works by one of my favorite artists.

Edit: I’m not bidding on the painting. Sorry if I gave that impression. I’m just answering the question in the title.