One other way around this "must charge the same for the same code" garbage that makes it difficult to be compassionate to a working uninsured, that is done by some who do cash practices (eg. simplecare.com)takes advantage of what we learned from the grocers during the days of wage and price controls.
That is: While it is TRUE that I must charge everyone the same price for a 99213, it does not mean I have to CALL it a 99213. For the cash patient, I can call it a Office visit-medium and it is $50. the same as the discounted fee schedule. Just never CALL it a 99213. or equate the two. It is an uncoded visit.
btw.. you then also do not need to bother with jamming the visit into some icd-9 slot either.
It was medium office visit for sore throat and fibromyalgia... that you charged $50 for - and since the visit never goes elsewhere for claims. NOT coding it not only saves you hassles of coding, it saves you risks from the poor put-upon insurance companies and the Gov't who is here to help....

JAA