某英语报举办以勤俭节约为主题的中学生英语写作大赛：要求参赛者根据以下四幅图内容，用英语描述发生在李华身上真实的故事并阐述其意义。

注意：1、文章的开头已给出，不计入总词数；
2、词数120左右。
参考词汇：节俭thrift
One day， Li Hua went shopping in a supermarket. At the checkout, he had to buy a shopping bag for what he had bought.
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