buy recipes on ah and sell to vendors for much more!

Good way to earn easy money is by selling recipes for lots of money which you buy very cheap!
Best sellers are brothers knaz and gnaz blunderflames in STV http://thottbot.com/?m=23421&s=b
They sell Schematic: Deadly Scope and, Schematic: Mechanical Dragonling.
You can only buy one of each per day. Mechanical dragonling costs 1 gold each ( you can easily sell it for 6 gold), and Deadly Scope costs 20 silver, which you can sell for 4-5 gold!
Another nice recipe is Mithril Mechanical Dragonling which is sold by Ruppo Zipcoil in hinterlands http://thottbot.com/?m=42274&s=b
It costs 40 silver what you can sell easily for 5-5.50g. I earned about 100g per week. This isn't a very high income, but its very easy! Along with that but the profit margin is extremely high. (Depends on realm social status how much you sell)