It depends on your location. If you are in Canada, charges will automatically appear in CDN dollars. If you are in the US or international, you will automatically see USD.
To see pricing options, log into your account and click on "Upgrade". Subscription prices will be displayed on the next page, where you will be able to read more about the subscription benefits and costs, before being asked to enter your payment information.
As a reminder, all subscriptions are considered non-refundable and will automatically renew until cancelled. Be sure you understand what you are purchasing before you complete the subscription process.