When your site is hosted by some of the free web hosts, you will find it very difficult to get it listed in a major directory like Yahoo! Although Yahoo! will never admit that it won't add a commercial site which is being hosted in one of the free web hosts, in practice, it will be a miracle if you can get your site listed by Yahoo! Listing your site with Yahoo! is difficult enough even when you have your own domain. Don't make your task more difficult than what it needs to be.