Audible is mainly a paid service, even though trials and promotions are common. In other words, Audible is not something you should judge by the headline alone.
That headline answer is only useful if you also understand the practical limits. On Audible, free or entry-level access usually means living with the meaningful question is not whether you can sample it for free but whether the membership logic suits the way you buy or listen to books, which can be fine for casual use and frustrating for regular use.