It's a classical rental system. You never ever own the software, regardless how many years you pay.
Do you know anyway I can get the whole software without doing the renting thing.
You can purchase CS6 from Adobe, but it's getting really long-in-the-tooth. You will never lose your files on your computer if you stop paying for your CC subscription. The software will just stop working to load it. But you can always re-subscribe if you need to access those files again for some reason.
Again, you can purchase CS6 from Adobe if you really want to, but you will be missing out on a ton of new features (and you probably won't want to upgrade your OS after that either because support for future OS's is uncertain).
I want to buy a software from Adobe and it keeps coming up with several monthly plans,...
Are the monthly plans like renting a house where you live in the house, but you have to pay rent every month, and once you can no longer pay the rent the house throws you out...
That's pretty much the situation with Creative Cloud -- the software deactivates 90 days after your last rent check.
If ownership -- defined as having a perpetual license to use the software -- is more important to you than having the latest and greatest versions, you can still purchase CS6 as described above.
If you do so, understand that eventually CS6 will become inoperable when running on future operating systems. If that is of no concern to you and you just want to use CS6, your current machine will become a legacy machine, frozen at a certain point in time.
If you want new features and some day, Adobe's promised improvements in performance, you'd better start ponying up them monthly rent checks!