This app allows the user to input the meals that they eat often along with the ingredients that are needed to cook the meals. The app then allows you to choose which meals you want for the following week, you select the meals and the list is generated. You can delete items off the list as you shop, making it easy to track the ingredients you have picked off the shelf.
Over time you will build up a wide variety of meals in your stored meals, and the time to create your shopping list for the week will literally be seconds.
There is functionality to add items to a general list that can be used as a more ad hoc list.