There are a lot of licensing restrictions that will make it extremely hard, if not impossible, for you to buy this from a third-party vendor. You'll need to sig

There are a lot of licensing restrictions that will make it extremely hard, if not impossible, for you to buy this from a third-party vendor. You'll need to sign a PAF(https://postalpro.usps.com/NCOALink_PAF https://postalpro.usps.com/NCOALink_PAF) with the NCOA service provider and if I remember correctly the smallest "batch" of addresses that the licensee can run at a time is of 100. The service provider also cannot run addresses via NCOA without actually sending a piece of mail to the address being processed. Source: I helped build a USPS CASS-certified address verification and NCOA API at my previous employer. Dealing with USPS licensing was a PITA.