Bob, since you got no responses here I wrote a PM where I gave some examples of approaches I've received out there. I worked in various frameworks.
I thought of another difference. For online teaching it's probably more like to be an adult student, and they'll be more tech savvy. The situation is going to weed out those who can't create/support a tech set up.
I'm sure I could pay on-line for in person lessons but I've never done it that way. It's probably an age thing. My children don't carry cash, they buy stuff with plastic. I've paid by credit card just for Skype lessons. I have a PayPal account but rarely use it, there's a fee on that too(except for family usage, which this is not. They don't check but I'm not going to be dishonest.)I think it costs my teacher an additional 2.5% to take the card, and I'm willing to add that to the fee, but he's never asked.