Finding cheap goods for ebay

I’ve been selling on ebay for about five years now with some success but mainly buying bulk items from other sellers and selling individually for a profit.

What I really want to know is where some sellers get here goods from as sometimes the items are so cheap I couldn’t even source them for their prices!

Where on earth do they get their wholesale supplies?

I would like to become a permanent power seller but have yet to find the secret suppliers where I can get goods as cheap to compete with the existing sellers. I appreciate that those with good suppliers want to keep them secret but after searching the net for hours I still can’t find wholesalers to compete for specific items like electronics and jewellery.