I have bought and sold coins on eBay for over 20 years. The cost of PP is baked into the purchase price IMHO. I would Never use F&F as it is too dangerous. High ticket items >1,000 in my case go signature confirmation and registered mail if being sent to a grading company.
I have never had a big deal go bad and my total sales approach 150K. I am Not a professional dealer, just a knowledgable enthusiast.
Trust, but verify is my motto. Among my dealer friends, personal checks are good that day on in person sales at coin shows.