Persephone got our new (used) car at a CarMax in Houston. It probably was a bit more expensive than a smaller dealership--not sure, since her sister works for the corporate office and thus we decided to just use her discount and not look anywhere else. However, just as a point of information, when I took the car to a mechanic the next day to have him give it a once-over, he said afterward that it looked just fine to him and then volunteered unprompted that "you usually don't have to worry too much about CarMax cars, because their stuff is pretty good." (That said, we did have CarMax rebalance the wheels before purchasing because we noticed that the steering wheel shook a little at high speeds, but that was a minor issue and they fixed it right away.)

Wherever you go shopping, I learned the hard way that it's a good idea to find out whether that dealer lets you take it to a mechanic for inspection before purchase, or whether you need to look around for a mechanic that will drive out to the dealer and do the inspection on-site. The latter do exist, but if you don't know that you need one before you get to the dealer, you have to rely on the dealer's recommendation of which one to contact. (In this case I just did an independent-mechanic inspection during the five-day return window, but I would've felt a lot more comfortable doing it before I signed anything.) You probably already know this stuff, but I didn't, so FWIW...