Well, I'll post what a coder friend of mine had to say on this. She says:
The first thing that comes to mind is that to state it
like that ("getting half the payment for their work")
is an open admission of a federal felony. If this is
someone you know, you might want to advise them to be
a little more circumspect about the payment
arrangements.
In my own experience, most nursing homes just hire
staff billers with Medicare/Medicaid experience,
although there are definitely some that subcontract it
(I would have serious misgivings about any that would
subcontract to an individual by offering "half the
payment," though, as that would be pretty irregular).
Many doctors' offices subcontract billing, as well.
Medical billing is a specialty of its own, like
medical transcription or coding (see
www.ambanet.net/AMBA.htm). As such, there are a
variety of training programs, both online and through
community or technical colleges.
I am not aware of any billers making unusually big
money at it, but that certainly doesn't mean there
aren't some who are. I know a couple billers and
their effort to income ratio is about average.