Simply buy it at Amazon or wherever you prefer.
Oki Yes i understand that, maby i need to be more clear.
Will my pics that i fixed in CC (under the test period) still be in my acount if i change to LR6 later (after my test period) ?
They have nothing to do with each other, but unless you uploaded your pictures to the cloud storage, I don't see how it's even relevant. Your images are just files on your harddrive and so is your LR catalog. There may of course be some minor issues like odd warnings about the sync missing, but ultimately the technical underpinnings are the same. It's just a licensing model thing.