Here is what I recommend:
Read everything in the manual, then read it all again.
Decide what your goals are with building a multicopter, and decide on a budget you can afford for your first round of your new addiction. Then discuss those goals with other members here to see which are realistic and which require adjustment based on your resources and the capabilities of the existing designs.
Then scrap all that and buy up parts with wild abandon, and forget the rules, just design, build, test and redesign to your heart's content.
Oh, and read the manual again. Then ask more questions.
I would suggest you start with the proven DiyDrones Quad.
And Mike is correct, READ the manual :-)
Buy an assembled board, in theory it should have been tested.
Really try to hook up with someone that is busy/successfull with quads.
There are a lot of little "catch you's" !
I help out at a local hobby shop, and have seen some hair raising assembly errors, from people that swear they read, and understood, the manual :-)
And don't be shy to ask questions here.
I am from India,from where can i get the components and what will be the custom duty charges?
Custom charges are specific to your country, can't answer that :-)
In South Africa, on Hobby Parts, we only pay a handling fee, and normal VAT.
I get most of my stuff locally though, some I import direct from jDrones