Why are so many websites charging a surcharge or fee if you use PayPal???

[espresso2]

For example, Aliexpress.com charges a surcharge of 80cents plus a percentage if you pay by PayPal. 

And it clearly states its a surcharge/fee for using PayPal. And not only them.

[kernowlass]

@espresso2

In some countries Paypal allows surcharging as long as its clearly stated before the buyer commits to pay.