A 4-credit course is $5000 and a 3-credit course is $3900 (don't ask me why the cost per credit for each are not the same). There is also a one-time $200 transcript service fee.
With that said, if your employer has an educational plan that can cover the cost, then it is definitely worth pursuing. I am working on a AI graduate certificate and have just completed CS 221. The level of rigor in instruction and course work is far better than any online MOOC course I've taken.