The available payment methods depend on the kind of purchase you want to do in Get on Board:
Individual unlocks | Credit or debit card  or PayPal
Boost | Credit or debit card 
All subscription plans | Credit or debit card 
Unlimited subscription plans | Electronic wire transfer (to accounts located in the United States, Chile, or Peru).
 Cards include Visa, Mastercard, American Express, Discover, Diners and JCB credit cards (from any country), debit cards (the US only), and cards from other countries authorized for international purchases.
Payment with credit or debt card is processed in The United States using Stripe, the industry-standard in online payments.