My husband is gone 4 days of the week so I have found with meat that I freeze the extra in one serving packages. Ground meat in patties as they thaw faster. I also grind and mix my own chicken Itailan sauasge but that I cook, drain and cool and package in single servings. So it can be easily put into pasta or mini pizzas ( using thin buns or tortillas.
Now I stil buy some things large as I love melons but then share it with friends and neighbors. It is fresher and does cost as much as a single serving.
Milk I also freeze in smaller containers. When I bought the single servings I found I was leaving it out of my diet. Not good so now I plan to use more of it.