It is unwise to spend your time on your badges on 2moons gold nether vortexes or epic gems; even though this can significantly boost your stock of cash it is not worth it. Many trinkets and offhand such as relics, totems and idols cost a few badges and can be a significant upgrade. These trinkets are essential in PvE and in many cases PvP. A usual set up of a PvP/arena geared player is that they will carry "Medallion of the Horde" and a Badge Trinket. To achieve these badges, you can easily reach around 25-30 badges a week just by doing a full karazhan run and the daily heroic.