I am from Mumbai but had been to Nehru Place, that's pretty much the Lamington Road of Mumbai. I guess you can pick a popular store over there such as Cost to Cost and Computer Empire. Many people vouch for SMC International too, but I had a terrible experience there.
Depends. When Amazon is giving flash sales, it was cheaper. Else, the costs are pretty much neck to neck. Some of the dealers on Amazon and eBay are from LR, so the price would be slightly higher, but you get home delivery.