Online shopping.why prices are low?

So i'm going to buy a nikon camera
i saw on some sites that were providing with this camera and that too at a stunning low prices (70% of showroom cost).
they were first hand cameras with all the accessories
i want to ask that why these sites provide these stuffs at low cost. Is it safe to buy my camera online?
i have never done it before
please suggest me

The business does not have to pay for running a shop and employees. However you do have to check it out because it could be a scam. If it's something well-known like Amazon or Tigerdirect you are probably ok. The only problem with all of these is what do you do if the item doesn't function.