I have seen the paintless auto dent repair. That is a cool process. Takes some skill and practice. I don't have any clue on the franchise.
One thing you HAVE TO DO. Look at the numbers. It usually takes some calls and sitting through the standard BS of "Oh, this is a great business!" But if they are legitmate, it only takes one or two BS sessions before they break out the balance sheets. Take a trusted friend (preferably educated) to sit in on those meetings. Two heads are better than one. Again if it is a legimate franchise, they won't mind your friend, actually encourage it.
Be prepared for the shock of "I take in this much, you take X amount and leave me Y" and how small Y is.
If your thoughts run along the line of "I take in this much, you take X amount and leave me Y" and Y is big. Look more closely, you are missing some numbers. Look more closely.
You can make money at this. Look at McDonnalds or any fast food franchise. They are OK models. Met someone that had 4 "Subway" stores, they were doing really well, with no BS. But their biggest complaint was trying to find good employees. That was their biggest area for loosing money.