You can't use a free version of Google Drive if you run a business. You'll eventually need to be able to turn off access for employees who leave, and run audit

You can't use a free version of Google Drive if you run a business. You'll eventually need to be able to turn off access for employees who leave, and run audits to verify that you're in compliance around data security. If you're on the free version, even if you have everyone re-create an account with their company email, you still can't administer anything and you'd be forced to ask your staff for their passwords in order to verify sharing access.