Are you worn out and your Monster Annihlation blessing is out of time and out of coin? There are some boxes, barrels and treasure chests that you can find laying on the floor on various different maps that can give you some extra coin and some useful consumable items.
As there is a limit where you can use this method it is not a reliable source for obtaining coin.
Another way is doing events. There should be some events that reset after every week for daily timed events that require attending at a specific time of the day.