Do not concentrate on choosing the car that appears to have the least amount of damage, choose the one that fulfills your specific needs or your project. It will save you a lot of money. Analyze the risk factors. You save because you risk, but make sure you minimize your risk by making a careful choice. You only get ten pictures (see example) and a minor description of the condition.
Some damage is obvious, but some like theft or flood is very unclear. Some damage, like undercarriage, is also unclear but is often the fastest to fix. You have to get a feel for the car before you get it. Take a look at the same car but new. Notice the differences. Assess them. Just recently dozens of cars with average price of over $100K were purchased for under $20,000; but you have to understand what you are doing before you make that purchase.
“I put a dollar in one of those change machines. Nothing changed” — George Carlin
You on the other hand have power to change something.