I'm not talking about Sam Dawson, I mean Sam Walton - the founder of Wal-Mart. While I'm no Goblin, I do have a pretty solid cash inflow that is only regulated by my ability to put up with the randoms I find in the LFD system.
It's no secret that epic gems sell every day. With the release of the LFD systm, Triumph badges fall from the sky like Skittles, and epic gems can be had for just a handful of badges. An average heroic will net me five of these badges in about 15 minutes, if I'm really lucky I'll get Occ and pull in a monster eight badges for 20 min worth of work. HoS is probably the worst producer, as you'll only usually get four badges - what with so many folks skipping the rock and maiden boss.
Either way, it's fast and easy work and will also net me the bonus gold plus any gray items or enchanting mats. This isn't the real money though.
No, for my 20 minutes (assuming a slowish group) worth of play, and my average five badges, I've got myself a 10 badge gem that will sell for about 175g if I sit on it and watch the market. I've found that method to be a bit slow however, and instead I go for what I call the SAMs Club marketing method.
135g BO - gone by the time I can get from Dalaran to ICC.
Now Gevlon would call me some kind of M&S or Social for dropping my gems off this cheap, but I'm in the market for quick sales and instant returns. This method would certainly be less benificial for a DPSer, but as a tank/healer I have instant queue times. If I'm really lucky and happen to get a mostly guild run, we can zerg through heroics in under 10 minutes. This sends my time to profit margin right through the roof. It's not uncommon for me to pull in 20 or even 30 badges in an hour (Gun'Drak takes 7 minutes for 6 badges in a 'mostly' guild run).
Considering that I don't buy flasks, food, or anything else to support my raiding habit - this is pretty good money in my pocket. I don't spend a lot of time doing nothing (though this is technically farming), and it helps keep me sharp. There is nothing like healing an 'at level' geared tank (or worse) and the overeager DPS that come with most PUGs to keep you on your toes.