Why had Madame Loisel's husband set aside an amount of money in "The Necklace"? What was he going to use it for?

The mainfrom
"," Mathilde Loisel, is very much concerned with how she is perceived by society, even
as she aspires towards a lifestyle far beyond her current means. In this story, when she
receives an invitation to a ball, she reacts with mortification and will only attend if she is
given enough money to purchase a suitable dress. To this end, she determines that four hundred
francs would be sufficient.

For his part, while her husband does have four
hundred francs set aside, he had never envisioned spending it in this particular manner. He had
been planning to use the money for the purchase a new gun, as he had plans of going hunting in
the summer. It was to that end that he had been setting the money aside to begin with. However,
the four hundred francs is ultimately used for the purchase of the dress instead.

As the story continues, this purchase itself proves insufficient to assuage Mathilde's
concerns (for while she now has a dress, she does not have any jewelry to complement it). It is
to this end that she ends up borrowing the necklace from her friend, Madame Forestier, a
decision which will ultimately lead to disaster.