Short Story

[Raggie]

I read a short story ages ago, I think it was by Stephen King. The story was about a man who could send death wishes by email. I dont remember much about the story but he was taken by the people he worked for and given an house with all his bills/groceries etc paid and given a small amount of money each week to spend as he wished. At the end of every week he had to get rid of the money he had left over which he did by throwing it down a grate outside his house. He was fobidden to get in touch with his mum and his old friends etc and kept in the house/town by the people he worked for.

Has anyone any idea what the story was called or maybe the book of stories it came from?
Thanks