"Free as in beer" means that it is something you don't have to pay for; no monetary cost; free=gratis. It does not mean whatever the article is saying and it doesn't mean that you're expected to pay back. See Urban Dictionary[0], Wikipedia[1].
Usually a free beer has an implicit cost... for instance, buying a friend a beer later, listening to a sales pitch, etc... Truly free beer is so rare, there's another joke that goes with it: "Free beer is the best kind."