The Monkey's Pay opens during a stormy night. The entire story takes place inside the White's house. There are mentions of things that happened outside of the house, their son being killed at work, but the whole story is set inside.
In The Third Wish, the story opens outside. It is a beautiful day. Most of the story is set outside. The story centers on a swan. So much of the story and the conversations take place outside. Only small parts of the story are actually set inside the house.
The similarities of the two stories settings are few. With The Monkey's Pay, the entire story is set inside a house. With The Third Wish, only small parts are inside. The very ending of The Third Wish is set inside, while the ending of The Monkey's Pay is Mrs. White opening the front door. The differences are immense. You can tell, just by the settings, that the two stories are different. Mr. and Mrs. White's story is all about selfish wants. Their wishes are made for personal gain. The setting being inside the house the whole time, shows a negative aspect to their wishes. It is almost a forewarning. In The Third Wish, you see that with the setting being in a more open, peaceful place, the story is going in a different direction. With the setting being in nature, we can see that there is goodness behind the wishes. Both stories try to tell us that you can't tempt fate. The settings of both, tell us more about the people who are granted these wishes.