CS6 suite editions and individual products are available for purchase via Electronic Software Delivery (ESD) on Adobe.com. Customers must pay with a credit card and will receive an individual serial number and download instructions.
If you prefer purchasing the cs6 versions of Illustrator and Dreamweaver ( rather than subscribing to creative cloud for the most current versions), you can download them at the following location: Adobe Store - North America
You may find this additional information of interest:
CS6 questions: http://www.adobe.com/products/cs6/faq.html
Just bear in mind that CS6 products are no longer being updated feature-wise and are several years old. They are sold on an "as is" basis, left to wither away on the vine by Adobe.
Whilst they do get the occasional security fix and other minor updates, they will not received any further new or enhanced features. Adobe's future is all in the Adobe Cloud so that's where all the marketing and engineering resources are going.
This may not be important for software such as Illustrator (where the CS6 tools are similar to current Cloud version), but it definitely matters for software like Dreamweaver CS6 (in the fast paced world of web development) which writes often-outdated code and sometimes uses outdated web techniques.
So if you hit a problem with your code and come to the Dreamweaver forums for help, there is a strong possibility that the response will be to update your software because the code is old, the feature you are using may not be in widespread use any more (so not many skilled people exist to help you) or even present a security risk.