Googling “learn Spanish for free online” yields over three million results, several of which are not, on fact free, as well as a massive amount of less than helpful links. After reviewing various sites, I’ve chosen and ranked my three favorites.
Study Spanish
This website offers conversational instruction through a CD set that one can purchase for $165, or it can be downloaded for $125. The free verb drills, pronunciation lessons, grammar and vocabulary sections are helpful, especially the pronunciation lessons which include audio for the student to hear and then repeat, ensuring the correct inflection.
Each unit also provides a written lesson, quizzes, tests. For a self motivated student, this would be a good choice. If you do well learning from reading and spoken example, this is a great option for you.

123 Teach Me
The first thing that I liked about this site is the translator on the left sidebar. There is also a verb conjugator, in which you can plug in a verb and the site with conjugate it out for you. A picture dictionary is easily utilized when a specific word is forgotten. Though it only covers six topics including cars, human anatomy, school, etc. There are also some great audio files that test student on their oral comprehension.
This site is much more basic, not a contemporary design but it does provide a lot of great tools that can be used when studying Spanish.

Jiffy Spanish
The format of the site is slightly unorganized and you have to sign up with your e-mail address before you can start the online courses for free. All of the courses are audio, so it’s perfect for those who learn through oral instruction. The site is promoting a product called Rocket Spanish.
This option would be the last choice for me considering the amount of work that one has to do to find the free lessons. It is more like a treasure hunt than an online Spanish class.