Shopping portals to buy things

Why we use shopping portals to buy things? that's the questions evolve and create many things. The reason is we get the things at cheap rate. we can compare prices from the things which we buying from market.Interesting article on the science of supermarket shopping, though I'm not sure the bread smell being pumped to the entrance isn't just an urban myth - please advise on any specific supermarkets known to do this and I'll happily be proved wrong... Now flowers at the front of store, that is more obvious. Provides the fresh scent, and lets face it who ever puts fresh flowers on the shopping list ? Definately an unplanned...