The sentence with the modifying phrase placed incorrectly is:
Ana wants to buy new athletic shoes from her favorite store once she saves up enough money, Shoe Empire.
The modifying phrase "Shoe Empire" is incorrectly placed at the end because it suggests that "Shoe Empire" is the store that Ana saves money for, rather than clarifying the store she wants to buy from. It can lead to confusion about whether "Shoe Empire" refers to the money or the store. A clearer placement would involve rephrasing to make the relationship explicit. For example: "Ana wants to buy new athletic shoes from her favorite store, Shoe Empire, once she saves up enough money."