Can I set up Zoho Books - Zoho CRM integration with Free / Standard edition of Zoho CRM?

Yes, you can. However, the Free plan of Zoho CRM allows you to set up only the Accounts / Contacts and the Vendor sync. You will not be able to set up the Items (Products) sync as the Free plan of Zoho CRM doesn’t have the Products module. Hence, you’ll not be able to access the Finance module as well.