Tell em to pound sand and tell the wife you do all the talking when it comes to selling the car. She may not wanna hear it, but it kinda sounds like she's the type they look for so they can walk all over them.
I've heard of the deals, maybe not scams, but people who either look for cars for others or buy them cheap and sell for a profit. Had it happen to me years ago, older gentleman gave me a sob story about how he just wanted a cheap, economical 4by. I fell for it, gave him a great deal, then saw it on a used car lot 2 weeks later. I was fawkin pissed man!