Discover's service is limited to only a few sites (which is why it's free). And it is not transparent about progress of removals or requirements.

That might not be the most effective way to reduce spam or reduce targeted attacks, because it ignores many hard to remove exposures.

We have a similar price point at Kanary (I'm the founder) and it covers the resources we invest in the cat & mouse game required to escalate and complete removals on a wide variety of sites, not just a handful of easy ones.