eBay has an affiliate program. Thus, if you send users to their website and the user places a bid on an item, you earn a commission of that item’s sale price [or you earn a per-click fee]. So, the idea for this website is that you basically scour eBay and find weird and cool stuff that is for sale on eBay; stuff people don’t ordinarily see for sale. The items all display on your website [you can use eBay’s API, or you could simply copy/paste item title w/thumbnail and use your affiliate link to link to the item for sale].
I’d definitely have a daily email newsletter, so you’ll want to capture visitor’s email addresses (“Sign up for our daily newsletter of weird and cool stuff for sale on eBay, now!”).