If you’re going to be an online personal trainer, do it right. If you’re looking at how to become a personal trainer online there are two ways to do it: 1  Take on a smallish amount of clients (10-20) at $100+/month.2  This is at least an extra $1,000/month! (and $100/month is a low price.). 3  Take a step back from training in person and commit more time.f you’re going to be an online personal trainer, do it right. If you’re looking at how to become a personal trainer online there are two ways to do it: 1  Take on a smallish amount of clients (10-20) at $100+/month.