Best/cheapest way to track down lead contact information

[Bob Burke]

I'm wondering if anyone has a recommendation for a "people find" service that is inexpensive and effective.  While driving for dollars I've found some obviously vacant homes, but county records provide no additional contact information other than the name of the owner and the address of the subject property.  I'm going to reach out to neighbors but wondered if there was an online resource...

Thanks for any insights!