Its only an effect of deflation, supply and demand. Deflation is basically prices moving downward. What has been occuring for the last two years has been a decline in purchasing because of values retreating.
You can argue that for the last 6 or 8 years prices were getting out of whack and we are now going thru an adjustment.
People wait to purchase until they see proof prices will no longer go down. So, unless a person has a need to purchase, he waits.
Now, the pendulum has swung too far the other way and prices are real cheap for certain products.
Here is a link regarding deflation:
http://en.wikipedia.org/wiki/Deflation