How would you explain the motivation for Mrs. Sommers' shopping spree in "A Pair of Silk Stockings"?

In Kate Chopin's "A Pair of Silk Stockings," the
protagonist Mrs. Sommers finds $5 and initially plans to spend the money on clothing for
her children.  However, when she goes out shopping, Mrs. Sommers is torn between
fulfilling her assumed role as a good mother and her inner desires for freedom and
individuality.  Her family has little extra money, so Mrs. Sommers has always put her
children before herself.  But this time she cannot remain confined to the strict role of
motherhood into which she has been cast.  Mrs. Sommers is motivated to go on a shopping
spree by her inner desire to express her individuality--she is tired of thinking of
others before herself and never doing what is in her best interest alone.  The shopping
spree is a symbol for freedome and expression.