New cars or used cars, which are the better deal? The moment a new car leaves the dealership it's value falls. The answer is a lot easier with that information. Since a car is a depreciating asset, meaning in general cars lose value with time, the best money decision is to purchase the car when it will tend to lose less value. Balance that with the time when the car won't need as much repair work. Those states converge in the slightly used car. The largest decline in value has already happened. That loss went to the original owner. The auto is likely still under warranty and isn't in a state of needing constant work.
There are many places to look for late model used cars. People who buy or lease new cars trade in their old ones to the dealer. Those vehicles are looking for new owners. eBay has a whole division dedicated to used cars, while specialty companies such as Carmax list thousands of them. In America there are car auctions every weekend. Auctions include cars from the police, taken from criminals, or used rental vehicles.
The most trusted source for used car prices is Kelly Blue Book. Cars are shown by year, model, then with prices shown for various conditions. It also breaks down the prices between dealer sales and private sales. Dealers have overhead private sellers don't have so that is important.
Have you considered financing? The better idea is to save money to make a cash purchase. No matter how low of an interest rate or how low the monthly payments, nothing helps the monthly budget like not having to make any car payment. It's nice to own a top of the line auto. Remember, however, that even simpler models get from point a to point b. Buying a car like that used can not only help the budget, but creates less stress. Theft, wear and accidents are bigger worries for people with fancy cars. A scratch doesn't mean as much on a less expensive car.
Wealth isn't made by spending, even on a car. It's based on what you save and on net worth. Most rich people get that way by saving money. Good used cars help the budget.