Ruby is a terrible choice. Use a Node.js based static site generator. You could even host on Amazon S3 (super low cost but globally distributed and redundant)! Look at Whitesmith/Blacksmith/etc.
Pray tell, why is ruby a terrible choice? You can get a basic website up and running with Rails in less than 10 mins.
Because you're running a webserver which can crash or otherwise fall over to serve static content when you could be running a literally zero-maintenance alternative.