3 days in and getting some profits from the the D3 Auction House... one thing of note today was buying and reselling Encrusted Hooves... back to a merchant. I noticed that the cost of buying that commodity was less than the price of selling to the merchant, so I decided to take advantage of this and bought as many as I could afford (and as many as they had left). Instant 30k profit within a minute. (For people who put it on the AH and were expecting to make more money off selling this commodity at that rate... I have no words for you.)
I similarly take advantage of the fluctuating prices of gems which varies from 160 to 300ish for Amethyst. Again profiting at 112 per gem (or more).
3 days, that's approx 1.2m in profits so far. Got three more weeks before results are tallied up. (to compare, I can get around 100k gold in one 20-30 minute run.)