Rakurakutei Ramen said:
This comic is the first time I've shown the shop (bitter smile). Their basic source of income is from Seren's activities as a mage, which is refining/selling magical medicines. (She's the world's leading mage, and since the effects of her magical medicines are strong, she naturally gets paid a lot.) By the way, the "junk" that Ginka mentioned contains treasures on par with national treasures or hidden treasures...