I've had a Kindle since Christmas, and don't think I could manage without it. You can read PDF & other documents on it, including spreadsheets, while it's not fantastic, it is readable.
Benefits of e-readers are that you can easily change the text size, and have a choice of background colours (Kindle anyway). The price is usually cheaper than a paper book (but not always), you can store many books on it at any 1 time (over 1,000 in the Kindle). There are many free books available, especially at the Guttenberg project (over 30,000), but also at Amazon and Smashwords as well. Almost all the classic books are available free including Dickens, which could be an advantage for someone wanting to improve their English. The built-in dictionary will help you as well. You can also make notes where you like, and return to them at any time.
Amazon also has a low priced special offer of the day usually £0.99 in Amazon.co.uk, not sure of price at Amazon.com