Yes, it is doable. I worked full time, and managed to take two classes my first semester, and a couple of other semesters I took one class and TAed another. Plan on having it take up all of our evenings and weekends. It won't always, but often will. For a couple of classes I even had to take some vacation days to finish up a project.
It is not up-front, it is per-semester. I think there is a relatively small application fee ( $50? ). Once in, it is ~$500 per course plus ~$300 per semester. So if you take one course a semester it is ~$800 for the semester, if you take two courses per semester it is ~$1300. The program requires 10 courses to graduate. For some classes you will need to buy a book or two, but many do not have any required textbook, or use a book available online.
I can't promise that all employers will see it that way. The ones that don't will lose out.