I work on https://monitoro.co which offers exactly what you're looking for, and is not limited to terms of service.
We also allow you to filter changes for the specific ones that are relevant to your needs, and trigger 3rd party APIs or webhooks with the updated data, or a text diff.
We also allow you to filter changes for the specific ones that are relevant to your needs, and trigger 3rd party APIs or webhooks with the updated data, or a text diff.