Each organization is billed for the chosen plan and any plugins that have been enabled. Each purchase is billed separately based on the billing frequency chosen, either monthly or yearly.
Your complete billing history is available on the billing page. Your current plan and enabled plugins are listed in addition to canceled purchases and all charges.
All plans and plugins offer the option of yearly or monthly billing. When switching from annual to monthly a credit will be calculated in the same way as downgrading meaning there may be no credit. When switching to yearly from monthly there will always be a credit issued provided you are not on the last day of the billing cycle.
A list of all charges are displayed on your billing page along with a description for the charge. You can print your billing page and use it as a receipt for year end tax purposes.
You can add multiple payment methods to your organization however only the default payment method will be used for all new or recurring charges.
When you downgrade your plan during a billing cycle the pro-rated amount will be credited before you are charged for the new plan. If the old plan was billed annually the current monthly cost for that plan will be used to calculate the credit, thus you may end up with no credit if monthly price x months used is greater than the annual price.
When upgrading your plan during a billing cycle a pro-rated amount will be credited before you are charged for the new plan if your old plan was charged annually. The credit will be the price you paid divided by 12 minus the months you have used, thus you will always receive a credit when upgrading.