Yes, you read that right. The price/performance of your cloud computing infrastructure could vary as much as 1000 percent depending on time and location. High levels of variability have actually been seen within the same cloud service provider (CSP) processing the exact same job. This also means that the cost to you of processing the exact same job in the cloud could vary by this much as well.
This surprising result was discovered by a Rice University group, headed by Dr. T. S. Eugene Ng, that has been focusing on cloud computing. Recently they published their joint work with Purdue University: Application-Specific Configuration Selection in the Cloud: Impact of Provider Policy and Potential of Systematic Testing, in the IEEE INFOCOM 2015 Conference Proceedings. That paper took a first step towards understanding the impact of cloud service provider policy and tackling the complexity of selecting configurations that can best meet the price and performance requirements of applications. That work resulted in a collaboration between Rice University and Burstorm, a developer of computer aided design (CAD) software specifically built to support cloud computing architects.