How expensive is grad school, really? In the words of the shady guy selling watches in the alley, how much do you want to spend? There are a lot of factors that go into determining the value of a master’s degree, including return on investment, job market potential, and real master’s degree cost. But that last one – master’s degree cost – can be the trickiest.

The average cost of graduate school tuition is hard to say. Peterson’s puts master’s degree cost at somewhere around $30,000 to $40,000 a year; according to Sallie Mae, the average is around $24,000. But the average cost of graduate school tuition includes the highest and lowest, and can’t account for things like tuition reimbursement, grants, and tuition waivers.

So how expensive is grad school? Here are some factors to think about.

You Really Do Get What You Pay For*

The asterisk is there for a reason – it’s a cliche that’s mostly true, but it takes a lot of qualifications to really explain what it means to say “You get what you pay for” with master’s degree cost. The average cost of graduate school tuition is high any which way you cut it, but certain factors drive master’s degree cost up.

Prestige costs; that’s true of high-falutin’ private liberal arts colleges, research universities, and polytechnics – the places like Stanford, MIT, the Claremont Colleges. But it’s also true of the highest-ranked public universities – the flagships, the Public Ivies, the STEM giants. In fact, U.S. News & World Report Data shows that public university tuition has increased by more than half in the last decade.

However, it’s important to note that the reverse isn’t necessarily true, at all (and that’s where the asterisk comes in): cheap doesn’t mean bad. In fact, a low tuition doesn’t indicate anything about quality. It may mean that a college’s endowment is so large, it doesn’t depend on tuition; it can simply mean that the college is committed to affordability as a mission or value. At any rate, you can’t judge quality based on cost.

Tuition Isn’t Just Tuition

Let’s be clear: tuition isn’t a scam, but it’s not exactly transparent either. One of the biggest complaints college and graduate students have is that it’s often impossible to tell how much anything actually costs until you get the bill – and then it’s almost impossible to figure out what you paid for.

When you see the listed tuition price online or in the course catalogue, that’s not the cost of the program. Some colleges (but precious few of them) are totally straightforward in their pricing, and the price you see is the price you get. It’s much more common, though, for universities to manipulate their pricing by hiding fees – sometimes a lot of fees.

The average cost of graduate school tuition is only half the story (sometimes literally). Ask about the fees when you talk to recruitment officers. Be real about master’s degree cost, and if they’re not real with you, there are plenty of graduate schools.

Time is (Tuition) Money

Most master’s degrees assume that you’ll be studying full-time; that’s the basis for their schedule, and the basis for their estimation of how long the program will take – 12 months full-time, 18 months full-time, 22 months full-time. The average cost of graduate school tuition doesn’t change either way.

Once you make the decision to go part-time, costs can start adding up. (That decision may not really be a decision – lots of people just can’t go to grad school full-time, if they have to keep their career and care for a family.) Those fees start to kick in, for one thing; you’re still paying the fees every semester you’re enrolled, whether you’re taking one course or three.

Convenience costs, too. Accelerated master’s programs, weekend executive master’s programs, distance master’s programs – if they’re guaranteeing swift completion, most of the time, you’re going to pay a premium. Online master’s degree programs may look cheaper at first glance, but hidden fees can add up with less scrupulous schools.

How Expensive is Grad School for Me?

While you have no control over what a university charges, the cost of your master’s degree is in your hands. Education is a service; be a smart consumer. Ask questions, run the numbers, and decide what master’s degree cost you can live with.