PayPal is free for buyers to use; it doesn't cost them anything at all. Every time a seller receives money, PayPal charge a fee. Hope you understand this very well now. DON.
For sending no amount deduct and for receiving,amount may be deduct and may not be. If you are using merchant service than it will be 0.30$+3.4% etc If you are receiving money from USA companies. It is not necessary , you amount deduct.
As its all said above there are other Paypal fees as well which could even cost a buyer a small amount of fee in case if your primary currency is USD and the seller is accepting only Euros then you need to first convert your USD to Euros which would cost a small amount of fees due to poor currency exchange values provided by Paypal so there is a small amount of fee involved there for buyers as well in case they want to convert currencies.
No its not like that, if the buyer only accept Euro and if seller sends USD then buyer has to either open a currency in USD or to exchange the USD to Euro on which he needs to pay conversion fee.
Some sellers dont accept any other currencies like if USD is they accept then they would refund if you send Euro payments (lots of people do that to avoid currency conversion fees and poor exchange value) on other side if buyer does it before sending i.e. converts before sending then he have to pay the fees involved.