You can buy a Collaboard subscription with your Credit-Card directly in Collaboard.
When you are logged in to Collaboard go to this website:
Now you see the different subscription plans you can purchase.
(1) Choose the currency you want to buy with. You can choose between CHF, EUR and USD.
(2) Choose the subscription plan you want to purchase and click on "Buy"
Decide now if you want to buy a year or a monthly subscription. On the yearly subscription, you get a discount.
Put the number of users you want to get a subscription in the filed "Membership subscriptions". After purchasing you can add users to your subscription plan.
Enter a promo code if you have one and click on "Proceed to payment".
Now you are redirected to Stripe where you can pay with your Credit Card.
After successfully purchasing a Collaboard subscription, you see a new tab where you can manage the users to which you want to assign a subscription.
In the plan page you see the subscription you bought and the next billing and the expiration date: