You just never know what kind of revenue a magazine has, and unless you do know, you'll price yourself way too high, or way too low. For articles, I've had brand new magazines pay me as little as fifty bucks, and as much as $1,200. For fiction, I've had magazines of similar size, but radically different ad revenue, pay me as little as $150, and as much as $1,000 for short stories of equal length.
I always try to find out what other writers have been paid, or say, "Make me an offer." This puts the ball back in their court.