I just found this link and it sees it is from 3DR as well:
Its price is 199$ which is cheaper than the price in 3DR official website which is 278$ :
Are these two same so I can order from Amazon?
The first link on Amazon doesn't include the price of the GPS unit. At the 3DR store the pice includes the GPS unit by default. If you deselect the GPS option the price is the same.
I don't personally know the Amazon reseller, so if it were me I'd buy it directly from 3DR.
Just one more question.
Stand alone GPS is 90$ but when I order it with Pixhawk it is 80$. Are these two GPS same as well?
Yes it's an LEA-6H uBlox with compass. You get a discount when you buy it as a package! Spend the $10 you saved and get a GPS mast.
Thank you a lot Nathaniel!