Wayne
it costs you nothing (i forgot, i had to pay $1 thats correct one dollar for the interface - just go to admin options and see it there under interfaces)
as a matter of fact you make some money with it
simple cost structure - $40/year for the patient and you get to keep half of that
i dont do it for the money but for the ease and convenience
i am also going to implement recurrent and important follow up reminders thru email system to the pt that is automated - by the way all HIPAA compliant
hope that answers your question
