Switch between different languages on my website?

You don't have to pay for some extension but generally it is desirable to use some code (Javascript) to make the language switching easier for the site user.

If you search through the posts here I think there are several examples of ways it can be done. Also a search on the web might help.

The advantage usually of a paid extension/plugin is that most of the hard work has been done for you and you just need to follow a fairly straight forward set of install instructions.