For years, I have been using the Donquijote website to improve my Spanish vocabulary and grammar from home, and it has been beneficial to me, so I thought – why not share it? I'm not sure how it would fit someone who is just beginning, but if you already know some basics, it could be a great tool.
Their primary goal, of course, is advertising their Spanish courses in different countries, but there is also an option of free membership which allows you to receive a FREE weekly lesson + exercise to your email. You can also correspond via the site with other people who learn Spanish. I have been learning and practicing that way for a long time now, and my Spanish has definitely improved.
So, if you are interested in learning some Spanish online for free, go to http://www.donquijote.org/, scroll down until you see "Members Corner", and get your free membership.
… another example of how learning can be made interesting, cheap, convenient – and done from home.