It's 0.941 per hour. Do the math :)
But, dont forget this (from the FAQ):
Am I charged while my Droplet is in a powered-off state?
Yes. Your diskspace, CPU, RAM, and IP address are all reserved while your Droplet is powered off. If you want to save a Droplet for future use take a snapshot of it and then destroy it. You'll be able to create a new Droplet from the snapshot image anytime to bring it back online.