I am assuming you're purchasing a firearm and picking it up from an FFL dealer. In that case you have already paid for the firearm and the dealer is just transferring a firearm to you and will just charge a small fee for the service that can vary between dealers. The dealer I use most often charges $25 but individual dealers set the price at their own discretion. If you use one of the "preferred" dealers (listed in green) from this list it shows the last reported transfer fee from them: budsgunshop.com/catalog/ffl.php

Allen, you only pay your local FFL Dealer their transfer fee. This could be $25 to $45 with the average being $30. This is all you pay at pickup as Buds will have already collected the firearm price and taxes.

pay him a transfer fee and do paperwork the transfer fee amount
is up to the receiving FFL holder normally between $15.00 and $35.00

Allen, When I process a transfer at my FFL I pay a $35 fee for first firearm and $17 for each additional firearm on one background check (Form 4473) when I'm picking up several firearms on one transfer. That includes fee for the FBI background check and add state and county taxes on transfer fee.