Ebay doesn't know how much you'll receive, as they aren't involved in the payment process. Payment goes direct from the buyer's PayPal account or card to your PayPal account.
PayPal will remove their payment processing fees (and what they are will depend on a number of things, such as what type of PayPal account you have, where in the world the buyer is located, etc, etc) before depositing the balance in your PayPal account.
Ebay fees are billed to you by Ebay once a month.
So it us your job to work out what your fees will be, prior to listing so that you can work out how to accurately price your item. Ebay's (and PayPal's) fees are listed in the Seller Centre (link at foot of any page), along with everything else you need to know about selling here. And to see PayPal's fees and account types in full, use PayPal's Help pages.
@delticnapier12
