[lukevp]

This can be done with the Cloudflare free plan easily, so long as you use Cloudflare as your DNS. You just make an authenticated API request to make the DNS update, and there are off the shelf tools to automate this in the background if you don’t want to roll your own.

[majormjr]

I do the same with route53, a small Python script runs on a Raspberry Pi to get the IP address and then updates the domain record through the API.