Clearing BoT, BWD, And Firelands every week on 25HC will yield about 4-5k per character. 125g plus 5-9 loot drops per boss. I do this weekly on two hunters and a feral druid in addition to garrison stuff. DS is profitable too, but takes too long to be efficient imo. Avoid Conclave, it is less proftable than running Vanilla 5mans.
[Edit] Been doing this for ages and i still dont have Rag's mount. Yay RNG.