Robert_Charlton - 12:28 am on Jul 23, 2013 (gmt 0)
Interesting test. It reminds me that a while back I suggested to an ecommerce site owner that his prices were too high for his market. I don't know whether he's acted on it.
It's worth noting that the trick in any experiment is to isolate the factors involved. Here, I'd keep in mind that Google is in the middle of a "softer" Panda update, so there might be some ranking change independent of your price change.
After you run through this test, you might (if you want to risk it) try raising your prices again and seeing what happens... and then repeating the price drop test again. I assume that a faster and more random A-B type testing would not work for observing the effects of prices on ranking.
There are also longer term effects of price that might exist but which you might not see right away. Cheaper, while not always better, should obviously help when customers are looking for best price. I've seen a reputation for good prices (coupled with good service) attract inbound links in price-conscious areas online.
I'm looking forward to future reports. Thanks.