Okay, Scooby - here's an example for you...
Let's say that there is three different members selling the exact same item - widget from here on out...and it's just the widget that you've been looking for to complete your collection of like widgets.
All three members reckon that said widget is worth $150 used.
Two of the three post in their FS threads that they want $150 + shipping + 3% PP fees.
The third takes a different route and asks $155 + shipping. The additional $5 in the asking price, of course, being to cover the transaction fee for accepting a PayPal payment.
All three sellers are asking for the same amount of money at the end of the day - are you telling us that you would buy from Seller 3 simply because his FS thread didn't specifically mention that the buyer would be covering the PP fees rather than the seller eating them and being glad for making the sale?!?