Startup Idea : Buyers Platform- Competition to the online market

Online giants like E-bay , amazon etc are all seller's platform.The seller are registered with an online store and they flash the items with best offering price.The buyer buys it from a seller who is offering good discount and good response rate.Now I am talking about just the reverse scenario.I suggest there should be an online buyers portal where he can raise his requirement through the buyer panel.Once he floats his requirement the sellers dealing in the stuff would provide him his best offerings.This will help offline seller in the same locality to get connected to the buyer.Since online marketing has made a phenomenal dent to the offline stores.