It's not necessarily the raw materials that incur the brunt of the cost of carbon. Cheap carbon can be made just as strong as the expensive stuff; you just have to lay more sheets. But there is a necessity for precision when producing carbon that will be bearing loads, such as pattern, amount of epoxy, and heat. Thus you want this stuff to come from a place with people who know what they are doing and know what to look for, not from some podunk factory that uses all the crap other people don't want to use and thus sells it for much less. Again, why do you think they are selling for so cheap? Didn't yo mama's teach you that you get what you pay for?