You will get the best price for either a monthly or an annual subscription by logging in at www.speedinvoice2.net/subscription/purchase from a computer or a tablet (the text is too small from a phone). An annual subscription gives you a 50% saving compared to paying for a monthly subscription.
You need a credit or debit card to purchase a subscription. If you don't have one, you can purchase a pre-paid card (search on the net).
You can also purchase an annual subscription with PayPal. Send the email address you registered with PayPal to support@speedinvoice.net and ask for an invoice. You can create a PayPal account for free here www.paypal.com.
Google and Apple sell monthly subscriptions through in app purchase. You can purchase a subscription by opening the purchase menu in the app.
Unfortunately you can't pay for a subscription with a bank transfers, as all of our subscription handling is automated.