Most large Cloud Providers have an arrangement with at least one email service which allows some free service (at least no extra charge than whatever one is pay

Most large Cloud Providers have an arrangement with at least one email service which allows some free service (at least no extra charge than whatever one is paying for the subscription), with a far higher limit than the typical free tiers - e.g. AWS/SES, Azure/SendGrid, IBM/SendGrid, GCP/Mailgun. So if you're already paying for some cloud hosting somewhere you likely have a free email service you can use.