There is no one definitive answer to this question. Depending on your individual needs and circumstances, there are a number of apps that could potentially help you find the cheapest car insurance. Some popular options include Moneysupermarket, Compare the Market, and Go Compare.
When shopping around for car insurance, it's important to compare quotes from a variety of different insurers to make sure you're getting the best deal possible. These apps can be a helpful starting point in your search for the cheapest car insurance.