Quick quide to prices at the beginning of the month December:

Here we have the prices beginning the month of December, the Christmas month. Surprisingly, prices have stayed very steady except for the prices of rares, which fluctuate hourly. Through experience, I have found that it is better to buy during the hours of 7-10am GMT, and sell later on in the afternoon, when Americans fidn the time to play, at about 7-10pm GMT.

Little changes through armour and things have been made, because earlier in the month, they rose, but since people have recently started to concentrate on the new skill, they have declined. Do not be surprised if they continue to decline also.
However, as Christmas is nearing, Santa hats are too, and this means good news for Santa hat owners. Still.. waiting a couple of years to sell if you plan on playing for a while longer will not hurt, as the will most likely rise more, since they have risen 20M in the last year.