A car rental in Los Angeles is considered by many tourists to be a reasonable necessity rather than a luxury. The city occupies a huge area and is very stretched along the coast, and the infrastructure of public transportation is not notable for its convenience. Cheap car rental in Los Angeles is a reasonable solution if you are going to be actively traveling around the city.
It's true that you have to consider the local congestion and parking issues, but on the other hand, many people in the city consider the freeway system to be something of an attraction.
Prices for car rentals in Los Angeles start at 30-35 USD for an economy or compact car. If you want to book a cheap rental car in Los Angeles, follow the advice of seasoned travelers: they recommend booking through brokers such as Thrifty, Auto Europe, Drive-USA.