Could I have some users in Professional and others in Free or standard in Zoho CRM?

Could I have some users in Professional and others in Free or standard in Zoho CRM?

I have 1 sales person, other that will imput and create accounts in the moment that they buy something in our offices. and the rest of the team are just read only users. I need Customized fields. Do I need to pay to everyone the professional Edition in Zoho CRM?