1999 Chrysler Town and Country window will not work

I'm selling my van and I had someone buying it but when they went to roll the window back up it stopped working. Her mechanic said it was electrical not just the window but connected to the locks and seats are all tied in. They were not sure what is involved in fixing it. It will definitely affect the price she agreed to pay for the van before the window stopped working. She is going to take it to the dealership to see what the cost would be. I know they always charge more. How much do you think it would cost to fix the electrical problem and should I take it to some besides the dealership?
Thanks, Bonnie