I have 2 different businesses. Do I need to purchase a 2nd subscription for my 2nd bz or is there a way to continue bookkeeping on one subscription for both?

One QBO account is for one company file. You can manage branches/divisions by utilizing the Class/Location feature available in QBO Plus and Advanced. Otherwise you should open a new account.

https:// quickbooks.grsm.io/US

https:// quickbooks.grsm.io/us-promo