Textbook prices are soaring into the hundreds of dollars, but in some courses this fall, students won't pay a dime. The catch: Their textbooks will have ads for companies including FedEx Kinko's and Pura Vida coffee. Selling ad space keeps newspapers, magazines, Web sites and television either cheap or free. But so far, the model hasn't spread to college textbooks -- partly for fear that faculty would consider ads undignified. The upshot is that textbooks now cost students, according to various studies, about $900 per year. Now, a small Minnesota startup is trying to shake up the status quo in...