Getting Ruby on Rails setup with a GoDaddy shared hosting account is rather difficult. This blog should hopefully take you step-by-step through the installation process. Remember there are a dozen things that can break a GoDaddy rails setup, which makes installing on GoDaddy's shared servers a pain. Fortunately, though, their low prices can in many cases make up for the extra work, especially if it's a small, personal project with little-to-no budget.
Start by purchasing a GoDaddy shared hosting account, but you probably already have one. If you haven't, though, you'll have to ensure that you have a deluxe or premium account - the basic level accounts don't support cgi, perl, ruby, rails, or any of those things. You can buy three years with 20-30% off, totaling a little more than a mere $100. Remember, though, life would be a lot easier if you can afford your own server, a host that specializes in rails, or a virtual or dedicated server. I'm assuming you're already stuck with GoDaddy.