I'm not sure if eBay can avoid Bitcoin forever. Sooner or later they are going to have to take a firm stance.
But I don't know how much they would charge for fees we all know ebay are famous for over charging.
The fee's are independent on the payment method, you get charged once per month with an invoice from Ebay.
But yes, the seller fee's on ebay is pretty high, you also pay 15% in VAT* on your sales, this will also be on your invoice.
*If you are EU based seller