Methodology: I grab the prices from Hex's daily Auction House dumps (just like everyone else). I look at the last 14 days of data to determine average pricing for both Gold and Plat. I get rid of outliers by using a simple statistical analysis (anyting above or below 1.5 * IQR for you stats savvy folks). I take the remaining prices and, using a moving average (which puts more weight on recent prices than on old prices), calculate the price targets for cards. This information is updated daily within four hours of the AH data being published.