You still have to pay for it because it costs money to make. But it’s completely open-source beer so you can recreate it yourself if you don’t want to buy it pre-made, or you want to modify the recipe.
I have no idea how to make beer otherwise I’d have a crack at this shitpost myself…
I’d just like to interject for a moment. What you’re referring to as Beer, is in fact, GNU/Beer, or as I’ve recently taken to calling it, GNU plus Beer. Beer is not an alcoholic drink unto itself, but rather another free component of a fully functioning GNU system made useful by the GNU hops, rye, and fermentation process comprising a full libation as defined by POSIX.