Core rulebook versions, which one to pick?

[Kelgriesh]

So i was interested in starting playing pathfinder.
The first thing to do was to obtain a core rulebook or players handbook.
This website (paizo) offers me multiple versions:
First Printing to Sixth Printing (v1.4)
Second Printing to Sixth Printing (v2.3)
Third Printing to Sixth Printing (v3.2)
Fourth Printing to Sixth Printing (v4.1)
Fifth Printing to Sixth Printing (v5.0)

I am confused as to which one to use.
If someone would recommend me one and maybe give an explanation why the selected one, id much appreciate it.

[Ascalaphus]

You need the sixth printing, it's the most recent one.

Those things you list there are documents showing what was changed between printings; mistakes fixed and rules changed between first and sixth printing for example.

Also, there's no separate players' handbook; the Core Rulebook has everything in it for both players and GM to start playing. The Advanced Players Guide is optional, extra, not necessary etcetera, although it is fun. But it's easier to start with just the core book.

Well, apart from monsters; those are found in the Bestiary. I recommend the first Bestiary, since that's the one the Core Rulebook uses when spells summon monsters and such.

[RHMG Animator]

When you buy the book check inside the cover and it'll tell you what version it is.

Those in the download section at the top are NOT the full versions of the Core Rule Book, but errata for each version of the Book.
You then select the errata for that version of book you have.

If you have the PDF of the CRB just re-download it, it'll be the latest version.

[Southeast Jerome]

If you're buying new, you'll almost certainly get a newer printing, but even if you buy an used older printing, it shouldn't be a problem. As RHMG said, the PDF is kept up to date and can be re-downloaded any time, and there is also a free online reference document that has all the rules content in the CRB and other core books. I tend to buy my hardcovers used, and I don't worry about the errata because I will use the online rules for my in-game rules questions.

http://paizo.com/pathfinderRPG/prd/