I got three Shadowfangs by using the Undermine Journal. Technically, I got them all for free by asking for gold. I just had to xfer them off.
Shadowfangs aren't really required. Get BIS minus the Shadowfangs, check theunderminejournal.com every now and then for a few months; you might get lucky, who knows, don't even worry about getting them until later because honestly, they don't make that much of a difference. Hell, if you want to save up the gold for them go for it, they run for 50kg-70kg ea, expect to transfer.
i came back to draenor without gold or maincharacter. You just have to be nice to the other twinkers and maybe know a few. I got so much help for my new twink from like everyone. Because of all that people who helped me im BiS(cba to transfer alliance and back horde just for ring) in 2-3 months and without gold or main on draenor.
BiS Rogues are not hard to do at all. Most gear is Dungeon gear the most you will spend is 2 Shadowfangs and maybe Feet of the Lynx and even that is highly doubtful. I bought both my Shadowfangs on Thrall-US for 687g for pair. Theey surface on realms dont worry bout that. If you wanna be the best get 2 Venerable Masses to substitute.