Thank you for contacting Linode Support! I see that you are on our Metered Billing plan. This plan is advertised as hourly billing. Under this plan, you will be charged on the 1st of each month for your usage in the previous month. For example, on the first of each month you will be billed $10.
Metered billing costs exactly the same as monthly billing. The "hourly billing" only comes into effect if you cancel or start a Linode in the middle of the month.
I hope that helps! If you have any other questions or concerns please do not hesitate to contact us again.