With Spot Instances, you pay the Spot price that's in effect for the time period your instances are running. Spot Instance prices are set by Amazon EC2 and adjust gradually based on long-term trends in supply and demand for Spot Instance capacity. To learn more about pricing, visit the Spot Instance history page. The following table displays the Spot price for each region and instance type (updated every 5 minutes).
Spot Instances are available at a discount of up to 90% off compared to On-Demand pricing. To compare the current Spot prices against standard On-Demand rates, visit the Spot Instance Advisor.
Spot Instances are also available to run for a predefined duration – in hourly increments up to six hours in length – at a discount of up to 30-50% compared to On-Demand pricing.
Note that you can now run Linux based RHEL and SUSE AMIs on Spot Instances. Learn more.