I know a lot of writers who are stuck on the rate per word form of payment. They refuse to work for less than $X.XX. They scoff at editors who dare to offer less than $X.XX.
And there isn't a problem with that, if that's where you are in your career.
In my case, I came from a job that used to pay once a month. Last day, that's when your check was deposited, everything on a salary, every month exactly the same. So my perspective is slightly skewed. I have an idea of what I want to make in an 8-hour day, or what my monthly income will be.
So, rather than get worked up about the per word rate, I look at the per day rate. How much time will I spend on an article from start to finish. That includes sending out the pitch, setting up the interviews and doing them, then writing the piece. I am blessed because I write fast, so that helps.
A lot of my work is repeat business from editors, so right off I get to eliminate the search part. Many of the articles I write are one-source pieces who are familiar with the magazine. Interviews usually take less than an hour. And so on. It's rare when an article requires more than 8 hours of work, so my "per day" rate is usually very good. Much higher than anything I made per day at the old job. Granted, I don't make money every day, but I look at what I bring in at the end of the month. I have a monthly goal and that's my real target.
The majority of my writing friends, particularly the trade writers, think in per hour rates. When they are offered new assignments, they calculate how much time they think it will take and decide what their minimum per hour rate will be. That's how they decide on what jobs to take.
There is no one right way to determine what is a good pay for you. But it is important to make sure you are being paid what you think you are worth. And that can be a post for another day.