eBay charges fee's to sell.
At the end of your selling period, you will receive an invoice from eBay. Either you can choose to pay them via Paypal, have an automatic payment set up via your checking account or Paypal or send them payment.
It could've changed...I haven't opened a new account with eBay to sell in many many moons.
Here's the eBay help link to the answers.
How do I pay my eBay fee's?
Good Luck,
Donna