While that is possibly true, it will nearly always have better up time than free hosting, simply as they probably have more to spend. The really big free hosters have good up time (by the large ones I mean bravehost.net and freewebs.com etc.), but they usually have by far the most restrictive packages and are aimed at very amateur designers.

If you meant cheap rather than free, it depends on what you want, so you'll have to be more specific.