Ethmoid is right... There ARE free web hosts, but... as the old saying goes "You get what you pay for" and if you pay nothing?
Most free web hosts are riddled with ads, and some are even hosts to malware. DO YOUR RESEARCH before committing to anything.
While some ISP's do provide free hosting, there are limitations with many of them, such as monthly bandwidth and file storage. You may not be able to get your whole site upto the server (depending on how big it is), or it may be down several days a month due to "excessive" traffic. Again - DO YOUR RESEARCH before committing to anything.
There are also a lot of services that run in the range of $4-7 a month for feature filled, bandwidth enabled hosting. Dreamhost is offering two domains for $3.95 a month right now. I use ICDSoft (have since 2003) and they're $7 a month, but they offer a lot for that.
Lastly, you want to look at SUPPORT. If your site goes down, and your "free" host is nowhere to be found.... It's as bad as having no site at all, if you cant get it fixed and no one can access your URL for days on end.