It depends.

I would expect the degree to cost between $10,000 and $40,000. I will include some examples of degree available:

The University of Phoenix offers a general MBA. It requires 39 credits. Their rate for graduate credits is currently $612/credit. Thus, that degree would run you $23,868.

The Tennessee Board of Regents offer an online degree program. They don’t actually offer an MBA, but do offer graduate degrees. They charge $1020 per 3 credit graduate course instate and $2283 out of state. Assuming 13 courses of 3 credits each, the degree would cost $13,260 instate and $29,679 out of state.

Another example from a state university comes from Kentucky. Morehead State University offers a fully accredited online MBA program. It requires 36 credits. They currently charge $295/credit instate and $785/credit out of state. That means the cost is $10,060 instate and $23,260 out of state.

Columbia Southern University is one of the cheaper online institutions, though I know very little about them (like whether they are accredited or not). They offer a 37 credit MBA. They currently charge $250 per graduate credit. That means their degree would cost $9,250.

Were I you, I would first look into online programs offered by the state universities in your area. They exist as a public service, not to make money. Therefore, their tuition charges are often in line with or cheaper than the for profit schools. The other thing, you don’t have to worry about accreditation. Most people know absolutely nothing about Columbia Southern University, but if you got an online degree through the TN Board of Regents program your degree might say “The University of Memphis”. People would know and respect the school (and likely the degree itself) more. Likewise, Morehead State University is a real, honest to God university. With a campus. And classrooms. And they are not going to close up in a couple of years.

Whatever you decide to do, good luck!