lego search engine

What are peoples thoughts on a search engine for lego sets, parts, and minifgures that draws from all second hand marketplaces? (ie bricklink, ebay, vinted, facebook marketplace) This would be more of a passion project and phase 2 of this would be integrating a way in which someone with an incomplete set can find the rest of their pieces for the cheapest way possible, whether that be buying individual pieces or buying another incomplete set. The website would essentially be a search engine...