Cheap Electronics Items in US

I'm curious... I shop on ebay a lot and I notice that people who live in the US are able to sell USB cords at rock-bottom prices, cell phone cases at dirt cheap, etc. I've tried to find sources for this stuff before with no luck... where do I find this stuff? I think I am interested in getting started with things like this but I have no clue where to look. Thanks.

You can find a lot of dropshippers here on the forum, as well as people who may have contacts for such. I'd check here first (services section). Alternatively, alibaba.com and other marketplaces like that have a place you can meet suppliers.