Where do Ebay sellers get their items for dirt cheap wholesale prices in bulk?

I was just browsing ways to eanr money online and discovered that EBAY is an effective way to do so. I heard it can be really fun hobby to get into… Buying products at wholesale prices in bulk and making some cash from it. I would really like try it out but with some small items small obviously. Does anyone know how to go about getting into that business? I’d appreciate some useful advice, thanks so much!