hi all , i just my first ever tourist visa to thailand. it's a 3 entry visa to thailand , can i stay in thailand 9 months (while doing in and out after 60 days and then 1 month extension) or 6 months with this current visa?
and can i later do another double entry tourist visa from cambodia? if so how many days do i need to stay in cambodia after i get my new double entry visa , or can i re-enter thailand the same day i get the new double entry visa?
i should also mention that this is my first ever tourist visa to thailand and i only visited thailand 2 times before.

3 entries = up to 270 days.

You can get other visas in Cambodia or wherever you like, and re-enter at any time the visa allows.

thank you very much.

You will come into Thailand, and they will give you a sixty day stamp, and you can then pay 1900 baht to get a one month extension. Once that's done (90 days), you've still got to leave the country and go to Laos/Cambodia/whatever, and then come back in. When you walk back in, they will give you the second sixty day stamp. Next time will be the third.

I knew a man who came in on a double entry tourist visa, he thought it meant that he could stay four months continuosly, he didn't bother leaving Thailand after two months. So, after a four month stay, he went to the airport and that's when they gave him a large penalty for overstaying !