In Artisan's Way, there is a well between the Alchemy Workshop and R&T's Sundries where you can repeatedly draw up to five units of water at a time. You can then sell the water for 1 Cole each at any of the shops; R&T's Sundries is just to the right of the well. You can earn an infinite amount of Cole by gathering and selling the water from the well. Although this is a slow process, the date will not advance. Do this if you need some Cole to buy materials for alchemy and do not wish to use up materials for quests or waste days by going out and gathering elsewhere.