In an attempt to actually quantify how the average price of items is dropping, I took a survey of items available at the AH based on 3 stats. Intelligence, Vitality and Resist All. As all 3 stats are desirable, I am going to take a survey of the auction house and see what is the best possible item I can buy (Intelligence > Vitality > Resist All). There are probably a lot of ways you would do this, but I hope this will show how the prices of items is varying over time.
Best item available for $125k or under (must have 5 items available in total)
(As of June 24th @ 6:35 PM EST)
Belt - 75/100/10
Boots - 100/75/20
Bracers - 100/75/10
Chest - 100/100/10
Gloves - 100/100/35
Helm - 100/100/25
Pants - 100/100/30
Shoulders - 75/100/15
Right now, less than 1 million gold would purchase this gear.
(As of June 29th @ 7:07AM EST)
Belt - 75/100/10 - $50k - New 125K is 100/70/10
Boots - 100/75/20 - Same - 100/75/20
Bracers - 100/75/10 - $65k - New 125k is 100/75/20
Chest - 100/100/10 - $90k - New 125k is 100/100/20
Gloves - 100/100/35 - $80k - New 125k is 100/100/40
Helm - 100/100/25 - $80k - New 125k is 100/100/30
Pants - 100/100/30 - Same - 100/100/30
Shoulders - 75/100/15 - $50 - New is ???