I recently opened the can of worms and have shipped multiple guns to PFers this summer.
I found a local shop that charges me the transfer fee plus actual shipping to box it up and send it out for me.
The most I’ve paid was $45 and as little as $27.
In most cases, I showed up to their shop with the copy of the receiving FFL printed out, with the recipient’s name and number written on the back. Then I put a piece of masking tape on the gun box with their name and # as well.
In the odd case, the receiving FFL didn’t accept from individuals so they didn’t sent me their FFL direct, I had to broker my guys calling them and getting it. That one was a trade anyway so it worked out that mine needed to send info back.
Had I tried to send it myself, I got quotes of over $100 from UPS for their required method and it was also hard to find the real hub that would accept a gun (apparently just any old drop off won’t work?).
ETA:
I’ve had great luck buying and selling at PF but a kind member did PM me to say I should raise my price and post on Arfcom because of his good luck selling a similar item recently. So ARF is my next stop...