We only accept credit and debit card payments for all versions of our product. This includes Balsamiq Cloud plans, as well as licenses for Balsamiq for Desktop.
We do not accept other forms of payment, such as PayPal, however most debit cards with a Visa or MasterCard logo (and that do not require a PIN) are accepted.
Balsamiq for Confluence Cloud and Jira Cloud are sold via the Atlassian Marketplace.