My cousin was on a recent show where he purchased one of the items they picked. He met Mike years ago at car swap meets, and has known him for years.
A lot of what is said here is true....Danielle does not work for them as portrayed, and for that matter, Mike and Frank aren't really in business together. The idea for the show came from Mike, and he is the one that pitched it and found someone willing to take a chance. He actually works more with his brother than anyone, and that is why you see him more and more on the show these days. Frank was an old high school buddy and Danielle was an acquaintance that he got to do the show with him.
Now with that said, they do actually buy and sell items, but if you have ever been to their shops, you know full well they are only tourist traps and not really making any money off of the actual items they have there for sale. it's a TV show, and nothing you see is 100% real.
Back to my cousin...he said Mike's brother contacted him to sell a certain piece, and when he balked at the sky-high price....it was explained he would be basically buying some national advertising exposure for his business and new podcast venture. The advertising has paid off a little...so he is happy he made the investment, and he and his daughter got to be on a nationally syndicated TV show. So the next time you are asking yourself how they find anyone to pay the prices that they do....you now know those folks are basically buying their time on the screen.