Also, I suggest searching for posts and information from someone on this forum named Auction Debt Eliminator if you are considering taking on auctions as a full-time seller/provider. I've read a lot of his words on here and he definitely understands the difference between a business and a hobby. If you've already sold grandma's old steam iron and that retro 80's Pac Man shirt on eBay, then you probably don't need any advice (you're a now a bona fide profit-making machine!) But if you are looking to create a sustainable business model, you may want to consider searching for the Eliminator's posts on this forum.
HINT: You can also use many of these sources for locating inventory if your savvy (or if arbitrage is your game.) And this list isn't even scratching the eCommerce surface, baby!
Maybe look up someone on this forum with the name Import/Export. I have not had his instruction or purchased any of his materials. But his bio and his experience are solid, so safe bet he knows his business. Just another avenue for those looking to tap in to less populated income streams.
With that said, I'll probably be getting the business end of Import/Export's boot for this next list...
Well, if you force yourself to become acquainted with the proper knowledge and guidance, you can find some terrific opportunities on these international sites. BE FOREWARNED, YOU WILL BE SEARCHING FOR GEMS IN A GIANT PILE OF MANURE, SO TREAD LIGHTLY AND SEEK EXPERT GUIDANCE - IF YOU RELY ON YOUR OWN CONFIDENCE AND ABILITY, YOU DO SO AT YOUR OWN RISK.
Finally, on to some sites for sourcing and saving... These sites can be great for any number of reasons, choose your own adventure!
DISCLAIMER: I am not affiliated or endorsed or WTF by any of the sites or people listed in this post. I'm just trying to share some quick information for the those with questions on what's possible and where. If you are new to selling, I strongly urge you to seek out someone with knowledge and experience to help stem the learning curve of going it on your own (something I painfully know far too much about!)