What will you be doing? Some places have “help desks” of personal trainers, which pays a low per-hour rate, but those trainers get several hours at a time helping clients who come to the desk, and they get visibility with clients without having to walk the training floor and cold-sell people.
If you’re not at a help desk, there is a HUGE variety of pay rates. I’ve seen as low as $12 per hour and as high as $40 per hour for employees (medium-sized metropolitan area). Independent contractors can make much more, but we also have to pay both the employer and employee FICA and medicare taxes.