I am interested in getting a “personal training on a sliding scale” practice established, what would be a fair price range?

Hello Christopher Blood,
You need to decide what is fair to both you and the client. The range I use is the bare minimum up to my full rate. Sometimes the client will start to take advantage; but, most of the time, the client is very appreciative and will pay more when they are able.
Another way around this, is to offer the sliding rate for a predetermined amount of time.
Discounted rates do not apply to farther distances, either.
Clients also have the group session option if they want to save money.
Take care,
Natalie aka NAPS 2 B Fit.