Amazon know volume, Amazon goes to suppliers on alibaba and gives them the quantity they require and then Amazon figures out what margin they'll be making if they sell it at the same or lower price than the original seller.
If you can't see volume, you can't estimate profit, and you can't differentiate which products are worth considering as a primary seller.
Start with volume as a suggestion of which products to investigate for purchase price with sellers. If you can get the "right" price with the "appropriate" volume, start selling the product direct.
Also, at Amazon scale, you can estimate margin by looking at price variation over time and throwing in some well tested assumptions.
> Also, at Amazon scale, you can estimate margin by looking at price variation over time and throwing in some well tested assumptions.
You really can't. You have to do research and modeling to figure out margins. There are probably half a dozen factors that determine a product's margin.
Amazon know volume, Amazon goes to suppliers on alibaba and gives them the quantity they require and then Amazon figures out what margin they'll be making if they sell it at the same or lower price than the original seller.