How much would you price rough sketches like these?

In USD please; based off of sketches busts!

They take about 10 minutes max to pop out a rough sketch here, so if I were to charge per hour rate of 10$ an hour, that's about $2. What do you say?

I think it's great to charge a proper hourly rate! $2 each seems good for these, and you can always bump up your hourly charge when you feel like your experience/quality of work has increased c: