Established in 1993, The National Council on Strength and Fitness (NCSF) is the cheapest accredited certification for personal training as of publication. The cost to take the exam is $199 in April 2011. You have three hours to complete 150 questions. Prerequisites include: a minimum age of 18 and a high school diploma or equivalent. Recertification is required every two years. This certification is recognized in the fitness industry