Use Domainr to see what's available.
Use DNSimple to buy and maintain domain names. If you already have a domain
registered elsewhere, like GoDaddy, DNSimple provides a transfer service that
makes it easy to switch.
We like it for its simplicity. It also has templates we most often need:
- Google Apps
- GitHub Pages
Follow the Custom Domains tutorial to set up root and
subdomains on Heroku.