The average price of a new car is just shy of $50,000. Whether you are a cash or lease buyer, that is a lot of money to shell out on your next set of wheels. Of course, you can always buy a cheaper new car, but even the most affordable new model currently on sale, the Hyundai Venue, is $20,550 before options, taxes and delivery fees.For that kind of money, you could find some great used vehicles across several segments, and that's just what we did. We narrowed down our selections until we had one example each of a sports car, family car, luxury car, and reliable car that was no more than six years old, had done under 100,000 miles and came in at under $20,000.We used AutoTempest to ensure that the cars we found were actually available at these prices. Let us know what vehicles you would chose in these categories in the comments below.Best Luxury Car: BMW 330iModel Years in Budget2019–2021Engine2.0L Turbo Inline-4Power255 hpTorque295 lb-ft0-60 mph5.3 secFuel Economy26 City / 36 Hwy MPGThe G20-generation BMW 330i may soon be replaced by the Neue Klasse 3 Series, but it remains the epitome of what a premium compact luxury car should be.Yes, we could have picked the equally capable 5 Series as our choice here, but going with the smaller variant allows us to get a newer example, and seeing as this is all about keeping things within budget, the 3 Series is also one of the most reliable vehicles in its class.For our $20k, we can get a decent 2019-2021 330i, in either RWD or xDrive. The 255hp 2.0-liter turbocharged four-cylinder engine is mated to a smooth 8-speed automatic transmission, and this combination provides great throttle response along with impressive highway efficiency.Best Sports Car: Ford Mustang EcoBoostModel Years in Budget2015–2022Engine2.3L Turbo Inline-4Power310 hpTorque350 lb-ft0-60 mph5.0 sec estFuel Economy21 City / 32 Hwy MPGThe S550-generation Ford Mustang EcoBoost still looks sharp and offers a driving experience that belies its age. The 2.3-liter turbocharged engine may lack the top end power of the V8s, but it is far more economical and very torquey.A simple remap can easily add an additional 20% more power and torque, but even if you keep it as Ford intended, the Mustang EcoBoost is a great sports car with space for four, a usable trunk and you can even find a convertible one at our price point.Best Reliable Car: Toyota CamryToyotaModel Years in Budget2018–2023Engine2.5L Inline-4Power203 hpTorque184 lb-ft0-60 mph7.6 sec estFuel Economy28 City / 39 Hwy MPGThe 8th-generation Toyota Camry (XV70) built upon its reputation for long-term reliability while adopting the Toyota New Global Architecture (TNGA) platform for enhanced body rigidity and composed handling.The standard 2.5-liter four-cylinder engine and 8-speed automatic transmission offer strong durability along with great fuel efficiency, and the optional V6 adds a lot more performance although at the expense of fuel economy and you will struggle to find one in our price range.For the best results stick to the four cylinder models that have a verifiable service history and you should get many miles of trouble-free motoring out of these solid cars.Best Family Car: Honda OdysseyModel Years in Budget2018-2023Engine3.5L V6Power280 hpTorque262 lb-ft0-60 mph6.5 sec estFuel Economy19 City / 28 Hwy MPGInstead of opting for yet another SUV, we chose the Honda Odyssey as our best under $20k family car. What it lacks in stylish design it more than makes up for in practicality, and you won't find an SUV that is this versatile for a large family at any price.Underlining our focus on affordability, it is powered by a 3.5-liter V6 engine that has been around since the early 2000s and should deliver many miles of fuss free motoring.The 5th generation Odyssey was introduced in 2018, and our budget allows us to stretch to a low-mileage 2021 model which introduced refreshed exterior styling and added fold-flat second-row Magic Slide seats. With sliding side doors and easy third row access, this is just the thing for school runs, and family trips.