Not "used". "Certified Pre-Owned".
I look for dealer program cars. My current two cars('15 A3 and '17 VW Golf SportWagen") have been dealer or manufacturer program cars. These are the cars that the employees get to drive for six months to a year, then they go on the lot as CPOs. The Audi was 6 months old and had 4000 miles on it, the VW was 11 months old and had 11,000 miles on it. I got both of them for 10k off the original MSRP, and both came with 6 year / 100k mile warranties, both were in showroom condition when I drove them away.
The more common alternative is to get a car off lease. These are usually two to three years old and mileage will vary. Fortune rewards the slow and steady shopper. My wife's A4 was 2 model years old when she bought it 3 years ago, it had 17k miles on it and she paid $27k, out the door. That's for a car that had a number on the original Monroney sticker of just under $42k.
Per the underlined above, it can take me more than a year to buy a car. That's because I first identify exactly what I want, then I spend as long as it takes for the exact item to pop up in inventory somewhere.