I checked around a few threads and didn't see anything with this method but it was just something I came across while shifting resources around this morning.
I believe its fairly common knowledge that you can take a cheap stack of netherweave cloth, turn it into bolts, make netherweave bracers/belt then DE the ~4g stack of netherweave into either 2-3 arcane dust (~4-6g), 2-3 Lesser Planar Essence (5-7g) or even get a lucky Small Prismatic Shard (~8-10g). (All of these values are based on my own server and could vary, making this either very applicable or not worth ones' time)
I had been doing this for sometime now, turning massive amounts of netherweave cloth into decent profit, or small profit if I buy the cloth off the AH. As I was surfing around today, I noticed that fel iron bars on my server has been consistently sitting at 12-13g a stack (ore reflecting similar numbers). With this, I have found 2 alternatives that cost less than netherweave (either as buying the components, or selling the netherweave cloth and turning those profits into purchasing these other mats).
Blacksmithing - Blacksmiths can create 3 different trainer-taught items that require only 4 fel iron bars - Fel Iron Chain Coif, Fel Iron Plate Belt, Fel Iron Plate Gloves. These items share the same D/E table as the netherweave bracers/belts but comparing the price of the 2, a stack of fel iron at 13g is much cheaper than basically 5 stacks of netherweave at 4g each (20g) for the same number of D/E's
Enchanting - I know theres a lot of options here with enchanting but I didn't notice this one either already posted so here it is. Golden Draenite Ring 1 fel iron bar, 2 golden draenite. A stack of golden draenite (not common), goes for roughly 10g. 2 Stacks at 20g, a stack of fel iron at 13g, = 33g for, thats right, 20 items to d/e. This converts out to roughly 1.65g per D/E for a result of items that will sell for a minimum of 4g up to 10g.