BookYourData prices Data Appending per record, with jobs starting at $499. Data Appending is a done-for-you service that fills the missing fields in a contact file you already own.
The price per record drops as the record count grows. You pay only for the records BookYourData fills. Files above 250,000 records get a custom quote.
Before committing to a paid job, request the free Data Appending test. The test fills 10 records from your file and comes back within 1 working day of the file arriving. The test includes a count per field of what was matched and filled.
For current per-record rates at your file size, visit bookyourdata.com/data-appending.