trumpisgreat16 is correct stating that buyers pay PP fees is against PP policy and any charge card for that matter. It is perfectly legal to add 5% to the selling price and offer a 5% discount if paying with cash, check, etc. The problem is what the item is worth is usually all people will pay. PP is a very good tool for a buyer and seller to pay each other. Using the feed back on Ebay and AGon also gives you an idea of the credibility of both parties. Yes, the 3% charge on big ticket items is a rip off.
I use PP for all purchases because the packing coming from some sellers on Ebay and AGon is pretty bad. It is the only recourse I have for bad packing. I also think the seller should pay the return shipping, when the packing is clearly at fault.
It is bad that the seller pays the fees and usually get the short end of the stick. When Ebay started, you sent money orders and cash to the seller before they would ship an item. I have over 5000 sales on Ebay over 20+ years and for the most part hate the outrageous fees they charge, but they have done much for the resale market of almost everything. Ebay has sided with me on a couple problems I have had with buyers, but for the most part they side with the buyer. I can also say, PP email me to not ship a sold $400 item sold on Ebay, because the card was stolen. Luckily I had not shipped the item. I would have been out $400 for sure.