Sellers adding for PayPal use is plainly BS

When you sign a mercant service agreement with a bank, you are specifically warned that adding 3% is in violation of the terms. Offering a 3% for cash is permitted (sematics). Someone must pay, there are no free lunches! (Second Law) In Asia, merchants almost ALWAYS add 3%, agreement notwithstanding. THey know this, as they, to a man (or woman)will NOT itemize said surcharge. Paypal is, well, not a bank. If the deal hinges upon 3% neither party is serious.

PayPal is not a bank. No bank freezes your money without warning. Only Police can shut you bank account, in my culture at least. PayPal can freeze your account when they dare, quite criminal act. PayPal is a greedy faceless monster that doesn´t give a damn for me not you. They only care for their asses. Total garbage. Period.

I have found that listing items where I include the PayPal and Continental U.S. UPS shipping, takes those two items "off the table", and makes items easier to sell.

As a hobbyist when I sell here (not often) I will clearly state; 
"No PayPal Fee's"
"Free Shipping"
"No Offers Please Fixed Price"
I'll factor the lowest price I'm willing sell something for including those costs.  
If the item is heavy I will charge shipping or sometimes be willing to work that with a buyer.

When I buy from a dealer in most cases if I read 3% for PayPal I'll pass. 

Whether you're the seller or a buyer, EVERYTHING is negotiable. Why sweat it or ignore a potentially good deal / transaction.