After iOS 7 came out, Apple made a lot of their productivity apps free on mobile devices! This includes Pages, Keynote, Numbers, iPhoto, GarageBand, and iMovie. I personally have typed many essays on the Pages app, and even made a couple of presentations using Keynote and iMovie, all from my phone! By the way:
Apple Pages = Microsoft Word Apple Keynote = Microsoft PowerPoint Apple Numbers = Microsoft Excel
AccessMyLibrary.com. Logs you in to whichever public library is closest to your location, and gives you online encyclopedias, textbooks, magazine and newspaper collections, and language learning services, FREE!
Quizlet is a great app and computer site to use when studying for tests and quizzes. You can either create your own study cards with terms and definitions or you can search for pre made cards with any subject.
You can locate the website at quizlet.com or you can download the app at the app store.