You want to sell some stuff and put up an ad listing items and prices. You want people to trust you to take their money and send the item as described. But hang on a minute you want the person your asking to trust you to add 3.5% PayPal fees for the priveledge!
If the 3.5% fee is such a problem don't charge £20 charge £20.70! And if it is a £300 pair of forks or a frame then there is surely even more reason to offer the buyer peace of mind?
I do find this whole "PayPal gift please" culture very strange.