We do not offer this option at present. Currently, we have subscriptions for monthly or yearly payments.
If you would like to just make one card or creation then you can choose the monthly option. Simply be sure to cancel prior to the next renewal date. Monthly has the option to cancel each month.
This will not affect your current status and you will have the features you have paid for until the next renewal date at which time it will renew or cancel depending on what you choose.