The domain is totally up to you: we can;t help you with that, as it should be snappy, unique, and - hopefully - relevant to the kind of products the user will find inside.
For example, calling your domain "JonesPlumbingSupplies.com" and then selling computer software is going to lose you a lot of potential sales. :laugh:
And since we have no idea what you are trying to sell, we really can't help you name your shop!
Think of a name - short is best if you are dealing with the public - and start seeing if it's available either locally (for the UK that would be a ".co.uk" address, for Ireland that would be ".ie", for India that would be ".in") or more globally with ".com"
If it is, put it on the "Possible" list, and try some more. Don;t ruch in - it's a big decision because once established, it's harder to change without losing existing customers.
You will also probably hacve to comply with local government laws on businesses, but
General Indian Topics Discussion Boards[
^] may be more help to you there than a "generic forum" such as QA.
Good luck!