When comparing the two schools my son is considering, we noticed an interesting data point: one school estimated books and supplies to cost $800 annually; the other $1,146. One of the schools my daughter applied to estimates $1,800. While I can certainly understand that different meal plans or living options might be more or less expensive at different schools, it’s hard to understand why books would cost 50% or 100% more from school to school.

We’re trying to make apples-to-apples cost comparisons, but we’re getting grapefruit and bananas from the schools. Why would they have such different prices? First of all, according to several unnamed sources, these are not numbers that are calculated in any detail. (One former public university administrator said, “We make that up.”) But a big factor is financial aid: students generally can only borrow up to the total cost of attendance, and that includes the school’s estimate of the cost of books and supplies. If school A budgets $346 more annually for books than school B, students at school A can borrow an extra $346, all else being equal.

So how much should you budget for books and supplies? According to the College Board’s Trends in College Pricing, the average undergraduate budget for books and supplies for the current school year is $1,240. But the National Postsecondary Student Aid Study said that students spent $900 on average on course materials and supplies, and the National Association of College Stores said that students spent $484 on course materials, with another $612 being spent on technology and supplies, and that this total has been on a consistent downward trajectory over the past 10 years. That’s a pretty big range, and one thing to note is “supplies” often includes a computer which would definitely tip the scale. But it probably isn’t something you’d buy every year.

One can generally assume that books would cost roughly the same amount for the same major, regardless of schools, which is how you should compare them. Why might there be variances in book costs between schools? Much can depend on the professors. An acquaintance who is a professor at one of our local colleges mentioned she stopped using a textbook because its price went up to $150 and she didn’t think students should have to spend that much. She also mentioned that she, like many other professors, is increasingly using free online resources. At the same time, one of her kids who’s currently in college was assigned an accounting textbook that cost $600. Another factor that can drive costs up: students attending smaller schools in remote locations might have less used books available locally. Then again, there are numerous online options.

If you’re concerned about this cost, reach out to schools directly to find out. Often online syllabi or course catalogs include the books assigned for the class so you can calculate what your specific classes are likely to cost. You can also reach out directly to the academic department to ask, or ask a current student when you visit the campus. And then you’ll want to research how best to get the books you need: buy vs rent, new vs used, campus bookstore vs online, …