The Recipe app keeps track of all your recipes, ingredients, and inventory. It will allow you to save ingredients, keep track of what you have, create recipes, and generate a shopping list based on what you have and what you are missing from a recipe. Also, since sharing recipes is an important part of cooking the app should allow you to make them public so anyone can access them.
The Budget App is a mobile-focused web application for managing your spending: you have a list of expenses connected with a category, and you can see how much money you've spent on what and which category. It also displays you which category you spend the most money in and your total monthly expenses, allowing you to make better educated financial decisions
A typical example of a blog website is the Blog app. I built a completely working website that displays a list of topics and allows visitors to engage with them by leaving comments and like them.