Buying snacks and treats at the store is really expensive if you think about it. Sometimes you pay around a dollar a snack, if not more, and the treats usually skimp on the good parts, like the chocolate. So, if you have the time, then consider making your own snacks in bulk over the weekend and saving them until you want to take them for lunch or are craving something sweet.
Homemade snacks are always better than their store-bought counterparts, and they are usually really cheap to make, especially if you make them in bulk and freeze them. You can also experiment with recipes.