For Erin, how about setting aside a portion of your appointments (perhaps half?) for clients who want to pay extra for a "membership" (or whatever you want to call it). They get one reading a month (or some other periodicity that seems appropriate, such as 6 readings a year). This way, the people who really apprecate and want to have you there for them regularly, without having to wait, can do that. The cost would be an investment to them.
And then the other portion of the appointments would be "first come first served", with a sliding scale rate, so that newcomers, curious folks, and folks who have lots of potential, but not a lot of money, could all have access to the services.
It seems to work well for a lot of different kinds of businesses, to offer that two (or more) tier format, with a level that everyone can access, and a level that offers more "ownership" for a higher price.
Peace, Love, and Bicycles,