Onboarding order: ask first to link Twitter account, or ask for creditcard information?

In an on boarding process I need a user to link their Twitter account and become a paid member. Although I explain both are required, what would you ask first? First make people pay, and then ask to link their Twitter, or vice versa?

I think this could go both ways. Depends on who your targets are. But a pretty flow would be social account -> payments