I have 5,000,000 candies and the blacksmith still says that he has nothing more to sell
Solution 1:
The scythe will only become available after you have visited the castle. Once you've visited the castle, go to the smith in the village and you will then be able to purchase the scythe.
Solution 2:
It takes a set amount of time before he has anything to sell. The last thing I got was the scythe, so I don't know if he has more after that