Class III AK-47
In order to buy it, you need to pay $200 to the ATF for a tax stamp, wait 6 months or more for their approval and then take delivery from your friendly neighborhood Class III dealer.
PS - After you take delivery of it, you would be required to send me a PM, inviting me to help you enjoy your new toy. ( I believe that's actually written in the law, in very, very fine print.)