I keep seeing a lot of these on the AH, usually ranging from 150-300g. I can't believe this many people are getting them by luck. So is it worth farming them? I feel like price on that will go up even more when phase 2 comes.

It'll probably go up in P3, because P3 is when WSG is released and when twinking will really become a thing.

I doubt they will increase in price by a significant margin anytime soon. People know exactly that the demand will increase, which creates a proxy demand driven by resellers. Their price may even tank in p3 when everyone thinks its time to cash in but the demand is a lot lower than what people imagined.

Difficult to give an accurate drop rate since the drop rate is different on different mobs, but I've heard people say that you can get one every 100 runs or so. Of course some people get them in 10 runs, some in 3, but if that doesn't seem like too much of an investment to you, go for it!