I don't believe so - the only digital option available at the moment appears to be the upgrade versions. They're essentially the same thing they just check for a key in your bios before installing, and require you to input the key if there isn't one before proceeding with the installation.
Using the method I mentioned above and using a retail disc image would allow you to fully install it without activating it. From there, go to the start screen and type "windows activation" to bring up the activation dialogue. You can buy a key with a credit card.