You'd have a hard time getting a job for something like this. Programmers can do art with this lack of form and poor colour use, so why would they hire an artist to do it?
To answer your question though: Take how long this took you, and multiply by the minimum amount of money you'd accept per hour working on art for other people (or the living wage in your country, if that's higher). You should never work below living wage, as that's essentially a waste of your time.
That might result in a higher price than people are willing to pay. That's fine - it just means you need to improve before you can get work.