I have not bought used car for a while, my last two used cars are both Toyota Pre own certified: basically I found the car online, went for a test drive at the dealership and bought them.
But this morning I had opportunity to visit a used car dealer in my old neighborhood: I lived near that place about 20 years ago. I remember the good old days, in late 1990s (1998 and 1999 to be specific), when I was a graduate student in Rolla (Missouri S&T), we would buy the St. Louis Post Dispatch newspaper on a Friday, went through the paper auto classified ads section, circle out the cars we were interested, call the private owners and made appointment for Saturday. And so on.
I was not familiar with used car dealers. I did buy a used Subaru from an auto shop (note his specialty is service not selling used cars). And I bought another used Subaru in year 2010, from an owner via local Craigslist. I drove that one for about 3 years and trade it in for the used Toyota Sienna in summer 2013, without losing much value.
Btw, I liked two cars I drove this morning, a 2013 Volvo XC 60 and a 2015 Honda Odyssey EX-L. Both came with about 144 k miles though – which is higher than my current own 2013 Sienna.