You also don't have to have a PayPal account to send money. The person that wouldn't send money without an invoice would have still been covered if they had sent to the e-mail address through PayPal. I rarely send invoice unless requested and I never use PayPal labels-why pay for something that is free on USPS? Also, when you use USPS the delivery confirmation is free and if you want other services you can get it there also. The only draw back is that you can't pay for 1st class mail on USPS.