As an NP who teaches others about having their own businesses and practices, I'd like to chime in here.
While working as an RN (and later as an NP) being paid an hourly wage, or even when on salary, I never worried about the overhead cost of seeing patients. Now, as a practice owner, I understand the reality all too well that time truly does equal money. Unfortunately, not everyone understands this reality.
Stop for a moment and consider the overhead (ie, cost to run the business) of any practice, hospital, community clinic. Overhead include (and are not limited to): lease/mortgage; salaries and taxes (often the highest/2nd highest expenditure); utilities (heat/air, water, sewer, garbage); phone and internet access; liability and business insurances; licenses; housekeeping; office supplies; medical supplies; lab costs, including those utilized for POC); billing personnel or billing service (quite high usually); professional services such as the CPA and attorney and a myriad of other costs...before the practice owner ever gets a dime.
Now look at the other side of the equation: a practice owner only makes money when patients are seen (unless you are seeing pts under a capitated plan as was explained by dudette10). There are several ways to look at this: cost per patient, cost per day, break even points.
For example, (using made up round numbers to make this easy). If the overhead cost per month is $5,000 (this would be a very small office), and your average reimbursement is $40.00 (it's often lower than this for Medicare/Medicaid), then the practice (and often the practice owner) does not make any money until 125 pts are seen that month. However, just because the patients are seen, does not guarantee that the practice will get paid. I am only half joking when I say that insurance companies are not in business to pay your claims.
There are many more variables that go into this, but I write this to give an example of what every practice owner must consider. As nurses and nurse practitioners who are employed, we would do well to learn a bit about the business of healthcare.
No one can provide services for free. Even if you volunteered your time entirely, someone has to pay for the cost of providing the service. There is no such thing as free health care. Period. Someone is paying.
And as a professional, don't you deserve to be paid?