Finally after some experience in buying on Ebay, I realised few tips for buying from Ebay
If the seller does not have 100% reputation feedback, dont buy
Seller must have at least 100 feedback, else dont buy
Reputation of the seller is very important.
If you are new buyer, some seller may not sell to you.
It is important to build online reputation
I had few bad experiences but also I had many good experiences.