"Ring Style Tones" gives 6 Google results, zero searches months and it's not a logical name people would type in so i would say about reg fee. Sorry.
I am not sure it will reach $xx unless developed to be honest, but I may be wrong so good luck with it.
There are many factors that play into a domains worth. Some of the top things to look for in a domain IMO are (not necessarily in this order): length - keep it as short as possible Must make sense - ie. does the domain name accurately describe the content of what the site is or will be. Memorability Number of results returned from search engines can also be a factor, but not necessarily There are many more factors involved as well, but remember to take any appraisal with a grain of salt. As with anything else, a domain is worth whatever you can convince someone to pay for it.