This question comes up quite a bit when discussing which tools are right for students, certain groups, or curious individuals.
How do you respond? I refer them to Jane Hart's blog or the Centre for Learning & Performance Technologies site where the Directory of Learning Tools (2300+) and the Top 100 Learning Tools. I encourage everyone to explore what works for them and what doesn't. This is one of the many advantages of online learning, find what works for you and the perspective audience. Better yet continue to learn and pick a tool a day or week and just try out a tool, read comments from others, and post your own comments and questions.
So whether you are a student, a budget strapped organization, or a curious individual visit the Directory of Learning Tools index ( http://c4lpt.co.uk/Directory/ ) and enjoy a site that provides an index consisting of a variety of learning tools, free and not so free, and where you can make a recommendation of a tool if it is not listed.