BookYourData charges nothing for a record that Data Appending does not fill. You pay only for the records BookYourData fills.
Data Appending is a done-for-you service that fills the missing fields in a contact file you already own. Data Appending jobs start at $499, and the price per record drops as the record count grows. Files above 250,000 records get a custom quote.
A free Data Appending test fills 10 records and comes back within 1 working day of your file arriving. The test result includes a count per field of what was matched and filled, which shows what BookYourData found before you pay anything.
To start a test or a job, visit bookyourdata.com/data-appending. More help articles are available at intercom.help/bookyourdata/en/.