Wow $20,000 is a lot of money. I really feel sorry for those i the states, when you consider I could enter a residence masters program in Sweden for nothing (coming from the EU) you really wonder where the cost of education comes from.
Not saying it's a bad deal, but it's not free.
It still might be the right choice for financial and non-financial reasons, but school isn't free even if you don't have to pay for it.