Yes, you as the seller pay fees to Paypal. The fees are not too bad for local (Australian) payments, but once you are dealing with foreign transfers it gets a bit exy. As an example, I sell a product for around $1400 AUD, and Paypal charges me about $65 each time someone pays from overseas.
The fees structure is there on the website.
https://www.paypal.com/au/cgi-bin/we...side&nav=1.0.1
Cheers,
Jason.