Nothing shows how much software architectures have changed than the intelligent scheduling of computation over differently priced compute resources. This isn’t just a false economy either. Vimeo saves up to 50% on their video transcoding bill by intelligently playing the spot, reserved, and on-demand markets. If you are ready for some advanced reindeer games then take a look at Vimeo EC2 transcoding where they explain their thinking.
That’s how the smart players win today. Requires you know what what’s important, and what can wait a bit longer until it’s done.