what's the best used cars I can get for 10k?
There are many good used cars that you can buy for $10,000 or less. The specific car that is best for you will depend on your personal preferences, driving needs, and budget. Here are some good options to consider:

1. Honda Civic: The Honda Civic is a reliable and efficient car that is known for its good fuel economy and low maintenance costs. You can find a 2012-2014 model in good condition for around $10,000.

2. Toyota Corolla: The Toyota Corolla is another reliable and affordable car that is known for its low maintenance costs. You can find a 2012-2014 model in good condition for around $10,000.

3. Mazda3: The Mazda3 is a sporty and fun-to-drive compact car that offers good fuel economy and reliability. You can find a 2012-2014 model in good condition for around $10,000.

4. Ford Fusion: The Ford Fusion is a midsize sedan that offers good fuel economy and a comfortable ride. You can find a 2012-2014 model in good condition for around $10,000.

5. Subaru Impreza: The Subaru Impreza is a compact car that is known for its all-wheel drive and good safety ratings. You can find a 2012-2014 model in good condition for around $10,000.

6. Honda Fit: The Honda Fit is a versatile and fuel-efficient subcompact car that is great for city driving. You can find a 2012-2014 model in good condition for around $10,000.

7. Hyundai Elantra: The Hyundai Elantra is a compact car that offers good value for money and a comfortable ride. You can find a 2012-2014 model in good condition for around $10,000.

It's always a good idea to have a trusted mechanic inspect any used car you're considering before making a purchase.
Which of these cars is the cheapest to run?
It is difficult to determine which car is the cheapest to run as it depends on various factors such as fuel economy, maintenance costs, and repair costs. However, both the Honda Civic and Toyota Corolla are known for their good fuel economy and low maintenance costs, which could make them more affordable to run in the long term. Additionally, the Honda Fit's fuel efficiency and suitability for city driving could also make it a good option for those looking for a low-cost car. Ultimately, it is important to consider factors such as personal driving habits, maintenance costs, and repair costs when choosing a car to determine which one will be the most cost-effective in the long term.