You do have to purchase a label, but you don't need a label printer.
You can print with a regular printer and paper and tape the label on to your package.
You can use the QR code option which emails a QR code to you, show the QR code at your local PO and they will scan it and print a label for you.
If you don't have a printer or a smart phone you can use the printer at the local library, Staples, friend/family.
Another option is to buy your label at the post office. It will cost significantly more, but if that's what works for you, it's an option. You'll need to save your receipt so you can add tracking to the eBay order.
Looks like you've sold a couple dozen items - what have you done for shipping up until now?
