Ask HN: Best way to do a startup in e-commerce?

I've been wondering for a long while now about the best way to start up in e-commerce. Specifically, I know there are some substantial costs associated with buying inventory, storing items, and doing fulfillment. From what I can tell, wholesale discounts only help with the former if you buy in large amounts, so you already need a substantial outlay. Does anyone have any experience/advice with this sort of thing?

Thanks!