I have a very specific, straightforward way in which I purchase my vehicles. I call, get bids from as many possible dealers, and then do the deal the following day. And I've done it many, many times for my family and extended family.
In my mission to find a 2015 Yukon, I talked to John and received a very competitive bid where the MSRP, Invoice, and agreed-upon price matched another dealer's almost identically equipped vehicle almost exactly, so I was able to compare apples to apples in two different deals. This vehicle was going to be leased, but I still negotiate based on the out-the-door price, as that's how it needs to be done. Curiously, the lease payment I was quoted was $30 less than the other vehicle. Even more crazily, I was told that it was literally a "sign and drive" deal - $0 due on day of delivery - which would've been another $2000+ that would've been rolled into the deal and should have increased the monthly payment.
To my knowledge, GM is not running a lease deal like that today ($0 due at signing) and would require, at minimum, your first month's lease payment at signing. I always pay license and registration at signing too because I don't want that rolled into the lease.
This is not magic, it's MATH. You can't scam a calculator. The math didn't work!
Once I compared the numbers and realized Liberty's were off, I called John back and left a detailed message about the issues I found with the numbers and to get some verification of the numbers I was quoted. That was earlier in the week and I never received a return call.
I believe that the lowball deal was a ruse to get me in the door and then go from there, or he never even had a car to sell me (low supply on Yukons). Either way, it would've been easier if I was dealt with in an honest and professional manner, and received a return call with an apology that either there is no car or that he wasn't able to do the deal he verbally quoted me for whatever reason and offered revised pricing.