Longer term subscription packages are typically better value per month. On the payment page, we explain the period that a subscription will last for, how much is works out at per month, and the amount that you'll be billed now.
If you choose to subscribe for a 3, 6 or 12 month package the whole payment will be deducted when you upgrade.
If you would like to pay monthly you will need to select the 1 month option.