Credentialing is involved and there is not an easy way to answer your question. First, if you've never done it, make sure you do your research to know what you are getting into. I wouldn't recommend getting into any fee negotiation is you don't have any experience. We charge flat rates for Medicare, CAQH, and each individual carrier. You could charge an hourly rate. When I do something like a CLIA license I estimate how long I think it will take (allow for follow up and submitting any requested corrections or info) and calculate a flat fee based on that time.