PayPal payment method is grayed out

I am confused, you said completing your first 'sell' listing? I thought you were asking about buying.

Ask seller to send you an invoice on PayPal. You can offer to pay any additional charge PayPal charges sellers.

Invoices for goods are very important to get Paypal protection, because, if just sending money, there is no protection at all from PayPal, it's like sending money to family or friends.

You could contact your credit card and ask about protection from them if something goes wrong.