$5-$7/month is the base standard for webhosting pricing.
There are a few that are cheaper, but I've yet to see one that is cheaper than that and still provides anywhere near the same type of service.
Often either theres nearly no support (when your site goes down it takes a week for it go be fixed) or the skim on other things. The most common thing thats skipped is PHP support and MySQL support, which is what wordpress needs.
I didn't catch that this isn't what you were looking for though, my bad about that, but finding a $15/year host thats even half decent is hard.
Finding one with PHP and MySQL support is extremely hard.
Good luck trying to find a host though.
Just remember, the two key things that it needs is PHP and MySQL support
http://wordpress.org/about/requirements/