For small websites sending transactional emails, implementing DMARC may be overkill and could potentially cause issues; prioritize configuring SPF and DKIM records correctly and monitoring IP reputation using online tools. If an IP block occurs, reputable third-party email sending services like SendGrid, Mailjet, Mailgun, Amazon SES, Postmark, and PostageApp provide cost-effective alternatives, often with free tiers or pay-as-you-go options, leveraging their established infrastructure and IP reputation. Gmail's SMTP server is another free alternative, but sending limits must be observed to avoid being flagged as spam. Explore cheaper SMTP relay services and DigitalOcean for setting up your own SMTP server, noting the technical expertise required. Monitoring sending reputation and avoiding OVH's IP space due to its poor reputation are also essential.