Mark Perry created the above chart:

The 812% increase in the price of college textbooks since 1978 makes the run-up in house prices and housing bubble (and subsequent crash) in the 2000s seem rather inconsequential, and  the nine-fold increase in textbook prices also dwarfs the increase in the cost of medical services over the last three decades. 

Jordan Weissmann puts the cost in perspective:

According to the National Association of College Stores, the average college student reports paying about $655 for textbooks and supplies annually, down a bit from $702 four years ago. The NACS credits that fall to its efforts to promote used books along with programs that let students rent rather than buy their texts. But to put that $655 in perspective, consider this: after aid, the average college student spends about $2,900 on their annual tuition, according to the College Board. We're not talking about just another drop in the bucket here.