I kind of see this as almost a reverse of ETSY in the sense that buyers could put down what they are looking for and small "independent" stores or sellers could reach consumers more easily. Obviously there would also be a Shop portion to it where people could list items to sell, but the main purpose would be for buyers to post something that they want to purchase, and sellers to reach out to them. I see this working in two cool ways.

First off, the buyer gives a price range and will only get "bids" in that price range to choose from, and will also most likely be exposed to cool things he/she didn't know were out there. Example: buyer makes a post saying "Looking for a sweatshirt without a hood. Size Large. Price range 15$-50$."

Then sellers would post/contact the buyer with their offer of a sweatshirt without a hood somewhere in that price range. Example: "Hey (insert cleaver username here) I have this (picture) large sweatshirt in stock for 25$." This way sellers who are having difficulty moving stock/independent sellers who want to get their product out there could have an easier time reaching buyers.

TL,DR see title.