Apple and Microsoft, both of which are leading brands in the tablet/computer industry, have education pricing for their devices to support students and educators and to facilitate the incorporation of e-learning in classrooms. Many electronics stores and outlets also provide discounts for students as e-learning is becoming more widespread and normalized.
Electronic textbooks are also much cheaper than traditional printed textbooks. According to Investopedia, the online version of a textbook can be up to 60% cheaper than its print equivalent, and if you already own a device to read it on, there would be no extra costs necessary. A quick price comparison on Amazon.com (e.g. "Economics" by McConnell, Brue and Flynn) shows that buying a new hardcover copy will cost $117.91, while the electronic version costs only $89.06. In the long run, when electronic textbooks become more popular in schools, electronic textbooks would prove to be a sustainable and affordable investment.
Overall, tablets can be afforded by most families and is not simply a luxury to have anymore.