I was contacted by CarMax twice during a 5 month period, finally decided to go ahead and interview with them the second time around, as it appeared they were interested in hiring me. Phone interview at first, then in-person interview. Study the interview questions on here and you will be fine. No big surprises. Then came time for the "Car Sale" presentation. I thought I did "OK" (I wasn't expecting to do great) however they wanted me to comeback and do it again in a few days. I came back and did the Sales pitch again (this time I did much better, by all accounts) and they still didn't offer me a Job. Found that strange, perhaps I'm too old? Not sure, but a little perturbed by it, not that I really wanted to work their to begin with since it's 100% commission.
Also, they have no Finance department at the dealership, you are responsible for the entire car Sale from start to finish. You are the Salesman and the F & I guy. That said, you should be making a whole lot more then the supposed $35,000 their Sales Associates average.
Last but not least they do conduct a MASSIVE background check. They have you sign a waiver that lets them get ALL of your employment history from the Social Security Administration. They then have you sign another waiver that states you didn't lie about / omit any previous employers on your application (which I did). I signed it anyway - im not putting down a few of my old employers for any number of reasons.
What ever the case they can apparently find all of your old employers via the Social Security Administration, so just be aware of that.