These are companies that offer you web hosting for your sites free of charge. Generally, they either show your pages in frames and insert their own advertising or redirect a percentage of your surfers altogether, which is why most Link Lists and TGP won't list anything hosted at a free host. There are a few occasional exceptions, like some free hosting offered by sponsors, but the exceptions are few and far between.

Free hosts are web hosting providers who do not charge a monthly fee for web hosting services. They allow users to share space on their servers at no charge, usually in exchange for a text link or ad banner on their web site.

a hosting service which allows you to host a website on there service in exchange for putting advertising on your site