You can add as many accounts as you'd like, as long as your monthly spend across all the accounts are less than the amount allowed on your current pricing plan.
If your monthly spend exceeds the amount supported by your plan, you will be upgraded to the pricing tier in the next billing period.
More info on pricing here.
For instructions on how to add more accounts, click here.
To ensure that your new account is on the same billing plan as your previous one, notify us on Chat Support.