That is no problem at all. You have two options: 1) You can use a subscription as a single purchase. Sign up for a subscription, receive the credits and immediately cancel the subscription afterwards. Your credits will be valid for a month and you will never be charged again. 2) Buy a package instead. Go to https://flexiclasses.com/mandarin-online/ scroll all the way down to the end of the page and here you can buy packages of 25, 50, 70, 100, 150 or 200 hours of group classes. These packages have longer validity and are a single purchase. Note: The packages are only available on the Mandarin page, however do not worry if you are studying another language. You can still buy the package and then just use them to study another language. All credits are fully interchangeable between languages.