Cisco Equipment on ebay

Guys, just want to throw this out there.
I have seen some very low prices on Cisco equipment on ebay and other equipment reseller lists on the internet. my question is, where do these people find these equipments at such prices? are they merely brokers? how do they make any profit selling at such prices? are these things fake or is there a source that i need to turn to for my equipment needs? if any one out there have any suggestions i will highly appreciate them.