There are many mail alternatives like Sendgrid as @neerja said.
Sendgrid free plan gives you up to 100 mail/day.
Another one is Sendinblue (which personally is the one I use). They have free plans up to 300 mail/day.
You can test our Sendinblue plugin here: ✉ Sendinblue SMTP A free alternative to Sendgrid mails by Reduble.com
You can create an account in Sendinblue, install the plugin and start sending mails in 10 minutes or less.