Before paying for a search you must check to see exactly what sources are searched, and how current the information is.

Even today, with more and more public records becoming available online, many searches for criminal records may still need to be conducted in person, at a courthouse by a human, especailly on the county levels.

Also, not all public databases resell their data, so using a public record portal like courtport in conjunction with using a professional search service will be the most comprehensive.

They record county filings such as liens, deeds, etc.  There are MANY counties in the U.S.

Courtport contains links to most of these public record databases, which are generally free to access.