Yes, you can import sales from eBay, theoriginaltha3r.
However, you'll have to use a third-party application to import. You can check the apps available in QuickBooks Online.
Click Apps on the left pane.
Type eBay on the search bar. A couple of available apps will show.
Select the best app you can use to integrate eBay and import sales.
Click the Get app now button.
In a new tab, click the Connect button.
Enter your eBay login credentials, then finish the integration.
You have the option to include a service fee for products or services you sell to customers. Please refer to this article link for future reference: Add service fees manually to invoices.