The only way to buy Fireworks CS6 from Adobe is by telephoning the Adobe Store (the number depends on which country you live in). Sales agents will not sell Fireworks CS6 if you are using an operating system later than Windows 7 or Mac OS X 10.7. This is because the software isn't certified for later versions of Windows or Mac. It is no longer available for sale through Adobe's website.
From Jan 1, 2013, only CS5 owners can upgrade to CS6. Everyone else must pay full price for CS6 or join the Creative Cloud. A new Fireworks CS6 license costs $299, I believe.
Fireworks was discontinued back in May 2013, and Adobe decided a couple of months ago to no longer sell full licenses of CS6 products online. Support, bug fixes, and updates are all gone for Fireworks. Support is DIY (Do It Yourself) and the FW user base here.
Having said that, Fireworks CS6 does still work on Windows 10. On the newest MacOSX El Capitan all sorts of compatibility issues exist: some users got FW running, some have it crash on them all the time, and others failed to make it work at all. Best to avoid getting Fireworks if you are running El Capitan. Or run it in Bootcamp, or Parallels in a Windows.
Hi Herbert, could you please tell me where I can find the sell agents list?
On the website: menu-->How to Buy-->Individuals.
The phone number is located at the bottom of the page.