1) My eBay - My account - Personal Information - Financial Information(нажимаете ссылку "PayPal account") - Link my PayPal Account
2) My eBay - My Account - Addresses - Primary shipping address - Change - PayPal address : This address is linked from your PayPal account - Make primary
На сайте PayPal.com :
Авторизируетесь :
My Account - Send Money - Pay For eBay - Items Add Another Account (и вводите свой eBay аккаунт)
