Public school teachers are certainly familiar with certain types of for-profit universities, diploma mills, and private and/or geared-toward-the-working-individual schools--National, Chapman, Phoenix, and LaVerne come to mind--as so many of us get master's degrees from them to move up on the pay scale.
It turns out that it's not only public school teachers who frequent such schools; military personnel are also a target audience.
I had a bad experience with one of these types of schools. I don't have a master's degree yet, but once when I was seriously looking at getting one I found one I'd truly enjoy: a Master's in Military History from Norwich University. I about bounced my jaw off the floor when the admissions person on the phone told me it would cost $40,000 for this online degree. I don't care if it's that much because most people who get this degree are active duty military who get reimbursed for the cost or not, that was just way too high. I don't care what kind of financial aid they offer, that cost is absurd. I don't fault them for charging that much if they think they can get it, but they won't get it from me.