It is no longer practical to send bulk emails (all emails sent from an Email Service Provider are classified in that way by Gmail, Yahoo etc.) using a free Email Address from any of the major providers such as Gmail, Yahoo, Hotmail, AOL etc. as the “Sending/From Address”, as they now delay, mark as spam or even block any bulk emails sent from such free addresses.
Gmail are also not supporting DMARC, yet another level of authentication, so using their addresses as a From Address is totally against their User Policies.
Many spam filters used by various Hosting Companies are now following suit so tusing any free email address has become a definite NO NO.