My girlfriend took a TOEFL course before her exam. From what she told me, these courses basically teach you the same thing as do some institutes before the placement season in your colleges. At the end of the day, you have to practice speaking and the other aspects like listening and writing yourseld, and no person or institute can help you in any way if you do not do that. The videos and threads in this forum are more than enough to prepare if you are seriously interested. My advice: Save your money, spend time with/in this forum, ask questions to people who have already taken the test, and PRACTICE yourself. If you do this, you are going to breeze through my friend!
All the Best!