I meant the yearly cost…the single 1 gallon (3.78 litres) bottle usually costs about 1 U.S dollar, or roughly .74 euros.
And yes, it rains. In fact, I live far enough north that it also snows…a lot 😆 …which gives me an idea where most of my water is going to come from. During winter I will try to collect as much snow as I can in buckets and store it in a large bin or bins with peat moss at the bottom once it melts. I have friends who would appreciate me depriving their lawns of a sizable chunk of their snow, so this should be relatively easy to accomplish without annoying anyone.