Priest is always a good choice for any player looking to fun a versatile healer class, but priest gold farming can be tough without the right spec and a general idea of how to DPS weak mobs. This guide is here to help with that.
The first thing to get out of the way is your spec; Shadow is the only real choice for a farming spec, the others having relatively weak DPS and mana issues. Something like this is generally best : http://www.wowhead.com/?talent#bVcbubZZ0xfVRfzffqfzAo:hIa
Once you have the spec, it's time to figure out how to use it! Shadow DPS is actually relatively complicated while raiding, but fortunately while farming enemies aren't going to last long enough for you to have to juggle cooldowns and DoT durations and figure out when to clip Mind Flays. Instead, all you have to do is the following:
0.Get all your buffs on: Inner Fire, Vampiric Embrace, Fortitude, Spirit, etc. before you start priest gold farming.
1. Vampiric Touch
2. Shadow Word Pain (can kite while casting this if you need to)
3. Devouring Plague (same, kite if you want)
4. Mind Blast
5. Mind Flay
6. If needed, you can use Devouring Plague, Mind Blast, or Shadow Word: Death to finish the mob off. Or just kite until the DoT's drop it.
Make sure to keep your mana up by using Shadowfiend and Dispersion often. Once you get skilled enough and geared enough, you can start hitting multiple mobs at once. Just make sure you have a Shield up, and put VT, SW:P, and DP on everything. Then go back to the first mob and finish it off with Mind Blast; generally that will be enough, thanks to the extra DoT ticks that have had time to hit the enemy.
As long as you are geared enough, Vampiric Embrace will easily heal any damage you take from the enemies; just make sure it, Inner Fire, and your other buffs are all active before you start your priest gold farming!
That's about all there is to it. Priest gold farming isn't at all hard once you have the right spec and know how to use it. Anyone looking to further optimize your gold earning abilities should check out my Gold Guide Review, where I compare various popular gold guides, and find one that sounds good.