It's one of the problems with China now being open to buy directly from ( via sign in china, ali baba etc.. ). People assume that everything in china costs pennies, and it is just the greedy western companies adding massive mark ups to everything.
Chinese sellers are not buying OEM parts from Japan or from Epson and then selling them for less than half the price legitimate companies charge, but people still fall for it.
Digiprint are a different thing though. A lot of what they are doing is dubious at best, and outright fraud at worst. They mislead people to believing parts are OEM Roland, when they are cheap chinese copies. A lot of these they don't stock ( when you see 3 or 4 week lead times ) - they just order from china when a customer orders it, add a big mark up and then forward it. They also claim they have their own special line of non original parts as if they are specially made for them....