Exactly! That's why, even if you can't find out what the other writer gets paid, you should have a limit that's worthwhile for you and stick to it.
I know it's easier said than done. I'm having a similar problem with the psychiatrist I wrote about in the ghostwriting thread - I met him and I think he's great! And so is his project.
So I'm in panic mode about the fee I will charge. So I have to remember, there's a certain limit as to what I can afford to take for this. Although it's a wonderful project, I need to be ready to give it up if it does not pay enough.
And I'll do so gracefully, because I know his project is truly worthwhile.
So, as you said, don't take less than $1000 for the article. They might say no. They might even act surprised. So just let them know you're a copywriter, so you're accustomed to the higher fees, but if they can't pay you that, you understand.
Or, they'll agree to the $1000 and you'll have a nice, lucrative project.
Janet