All new box purchases are charged right away. If you order your box after 12 pm EST on the 20th of the month, you will be shipped the following month's box.
Recurring Billing: Recurring charge orders will begin processing after 2am EDT (UTC-4), on the first (1st) of each month.
Example:
You sign up July 21st. You will be billed right away for an August box. Your box will be shipped to you in August. If you subscribed, your next billing date will be September 1st since you already paid for August box.
If you purchase your box on July 20th, your box will be shipped to you in July. If you subscribed, your next billing date will be August 1st since you already paid for July box.