Today cloud cost management company Cloudyn announced a new free service for calculating costs of Amazon EC2 Reserved Instances. Reserved Instances are sort of like cloud instances that you pay a retainer for: you pay an upfront fee, and can then pay a discounted rate if/when you use them.
Amazon offers Reserved Instances at different rates depending on term of commitment — either one, two or three years. Cloudyn’s Reserved Instance Calculator will use predictions based on usage patterns to recommend optimal purchases. Given that Amazon actually opened its own marketplace for unused Reserved Instances last month, it seems like a tool for planning these purchases could come in pretty handy.