I can see there are so many bitcoin website are there in internet, so how can we know about the correct and good bitcoin website where we can spend our time in good way.
It's simple,
you cant.
look the reputance of the site and older customers, it will help but unfortunately we will never be 100% because it's internet(look mt gox for example..).
If you want to, you can "gamble" in these ponzi/scams... some times they pay, sometimes they dont so it's like gambling.