Why can I only sometimes pay by Paypal?
Due to a change in Paypal's Terms, Gumroad can now only accept payment via paypal only if the VA links a paypal account. Unfortunatly, because of the nature of the stories we write, accepting payments via paypal carries a large risk of the VA's paypal's being shut down, so many don't link these accounts together.
There are services such as https://icard.com/, which allow users to create virtual cards, which may allow gumroad purchases that don't accept paypal without submitting your personal credit or debit cards.
Appolagies for any inconvenience caused.