If you do not want then you would never get banner ads or popup ads in your website. This is because unwanted advertisements do not help the business purpose of the website owners. It is true that the hosting sites make loads of money after selling the advertising spaces in the websites. Therefore you would often find the free web hosting services having advertisements which would also appear on your websites too.
When the banner advertisements were first started they were interesting but then they became over-used.
The web hosts which give forced advertisings on your site they often use the advertisings in the form of moving images especially in the.gif format. Often you would be forced to place the ads of the site sponsors on your website. However, you would find that there are various levels of forced advertisements in the websites. This means that one particular advertisement can be provided to the audience and have them exposed to force advertising.
Banner ads and the popup ads are the most prevalent among the force advertising medium. Banner ads are the ones to which most audiences are exposed. Though this is involuntary, the audience might not always perceive the banner ad. If you are exposed to forced advertising in your site then both you and the visitors in your website would have very little control over the banner ads. Often without your liking you have to tolerate the banner or the popup ads for a period of time as long as the web host decides.
These banner ads and the popup ads are believed to generate high revenues for the site sponsors and if you are on a free web host then you are more exposed to the problem of forced advertising than if you are on a paid web host plan.