The free SSL ensures secure entry of credit card details of customers.

 

Gateways:

SSL on your website is required by bank gateways like www.eway.com.au.
But it’s not needed by PayPal who have their own encryption.
Eway gets the money into your bank account same day. PayPal takes till the following day, usually.

No Gateway:

But to get the card details by email to you with the customer order requires encryption of the email.

S/Mime is a Microsoft program for that encrypting emails. Read about it at:
 https://docs.microsoft.com/en-us/windows/security/identity-protection/configure-s-mime

We have been running it for some time at  https://e-platypus.com/x/yourcompany.com.au/cards.php