I'm currently in the conceptualising phase of a startup idea I have, and rather than bringing my own unique product to market (which is a very complicated and expensive step at this point), I am toying with the idea of testing my platform and idea using similar products that have already been brought to market by other retailers. However, being in such an early stage of the process, I can't quite wrap my head around how I can realistically approach a big player in the industry without having anything tangible to offer them. I can't reasonably predict how many orders I can bring them, and need quite a wide variety of their product designs. Furthermore, I want to curate a collection from multiple brands. Basically, I will be setting myself up initially as an e-commerce retailer, before eventually (hopefully) producing my own products.
Does anyone have any experience doing this? What should I have accomplished before I approach these brands?