We have had AA frequent flyer memberships since at least the 80s and I don't remember there EVER being a fee to book, unless it was last minute. I know that US Air did have a fee to book FF seats.

Regardless, it all depends on where you are, as far as whether you can use them or not. When we were in DC, we always had good luck with getting them, and in Florida also. US Air or Delta, no. I have a bunch of Delta miles and cannot ever use them to get to SXM. We almost used them to go to Europe and ended up cancelling the trip.