Hi Dawn. The cost to become a certified fitness instructor varies with the organization or agency that grants the certification. It’s impossible to give an actual cost without knowing what organization you are interested in. What I would suggest is that you begin a ‘search’ into the various certifying agencies by first checking gyms in your jurisdiction to see what are some of the primary agencies that the instructors in your area hold. Then check with some of those agencies as to their requirements for getting certified and the cost.