Are you using the Laucke in the boxes or the bag? The bag of white or wholemeal is about $11 for 5kg and comes with the yeast sachets. I mostly use the wholemeal in the bag and have the sour dough box on the shelf for when I feel like something a bit different.
i got one of each (wholemeal and white) in the 5kg bag.

Is sour dough a different flour? ( i love sourdough)