you can't (one-time) purchase any flash/animate version from adobe.
there are 3rd party vendors (amazon, ebay) for flash cs6 but almost none are legit. ie, you'll be taking your chances.
the most likely legal purchase you could make would be from someone that's not a vendor but an individual that purchased flash cs6 years ago and is legally transferring their license to you, Transfer an Adobe product license. but people that sell their individual license may not deactivate all their previous activations and very few go through that license transfer process.
anyone that's selling a license that needs no activation (ie, an enterprise license) is selling an illegal license.
the biggest problem is getting a license that works when you first install it but months (or years) later, fails an authentication check. that's happened to quite a few people in the past few months because adobe tightened their authentication checks. they may also do that in the future. by then the vendor is long gone and you have no way to recover your money.
Alright, thanks a lot!