I am personally against online training programs. The biggest reason is that there is no contact between the trainer and client. I am a little curious about using something like skype, but still not personally able to get past the potential safety problems. And when I hear about online workout designs being sold to anyone that will click and print, it worries me more. How targeted can these workouts be if the user has never been seen using them or assessed? When people from outside my area ask me to give them a workout program, I recommend that they seek out a trainer in their area. I will even check out some local trainers for them. I may be old fashioned. I may be out of touch with the current trend. But I can’t get past the fact that what I do takes me seeing the client doing things in person to do the best job I can. And I spend hours developing programs for each client. Maybe that is why I solve so many issues that clients thought they would be living with for the rest of their lives.
I would do a combination.
Let’s say you have three online clients, one wanting a different workout for 6 days out of 7, the other being happy with 3 workouts, and the third just wanting one workout to repeat several time, then you should charge different rates.
For example, there could be a flat rate for 1 to 3 workouts and one for more than three. That could protect you from clients who want to get the most out of you for the least amount of money.
I would charge a flat rate as well. While each session may be a little different with regard to preparation (as Daniel mentioned), you can factor that into a flat rate slightly to reflect any variance. Charging clients different rates would be frustrating to them, I would think.