free is the best for business, good CS and most likely repeat customers. $10 is fair. $20 is normal. $25 plus is above average. $30 plus is pushing it. $40 plus is insane.
$20 is fair...and a nice, round easy to deal with number. A couple of the stores here in Marietta/Smyrna want $50 to do one...now that's ridiculous. I understand that some manpower time goes into logging a gun in and back out again, as well as the background check...but I have a GFL, so forget the check. $50 for a little paperwork is almost criminal...