I don't think it's possible to buy the SingBlazer on disc anymore. The only thing available is a download link that still works and it was provided on the support forums on the USCutter website.
Access the URL to see an overview about the SignBlazer and SignBlazer Elements as well as a user guide. According to the users on the forum, the SignBlazer listed on that website is actually the full version.
Tip: Use a burning tool to create a CD with the software.