I'm looking for a reliable used sedan under $10,000. I want something that can last a long time with minimal repairs. Which models should I focus on?

Based on the available data, the Honda Civic is the only candidate that might fit your under-$10,000 budget, but it comes with significant reliability risks. The Toyota Camry is simply out of reach, its typical used price range starts at $16,000, even for older models. The Mazda 3 has no price or owner data to evaluate, so it cannot be considered.

For the Honda Civic, you need to be very careful about which model year you pick. Owner reports highlight recurrent engine problems on specific generations: the 7th generation (2001-2005) with the 1.7L engine has head gasket failures, and the early 8th generation (2006-2009) with the 1.8L engine can have cracked engine blocks. These are serious, expensive repairs that would blow your budget. Later 8th generation models (2010-2011) are generally more reliable, but you'll still be looking at high-mileage cars under $10,000. Also, any Civic with the 1.5L turbo engine (2016 and later) has potential oil dilution issues in cold climates, though a software update helped. Rust is a common issue on older generations, so check the undercarriage carefully.

Given your need for a reliable daily driver with minimal repairs, the Honda Civic is a gamble. You could find a well-maintained 2010-2011 model with the 2.0L engine, but you'll need to budget for a pre-purchase inspection and potential rust repairs. The Toyota Camry, while known for long-term reliability, is not an option at your price point based on this data. Without information on the Mazda 3, I can't recommend it.

For your situation, I'd suggest looking for a 2010-2011 Honda Civic with the 2.0L engine and a manual transmission (to avoid CVT concerns) if you can find one under $10,000. Otherwise, consider expanding your search to other sedans not covered here, like the Hyundai Elantra or Kia Forte, which often fall within your budget and have lower repair costs.