Guy^ that rocker you put up a picture of is just covering the mess. If its rusting or gone already its going to need a whole lot more than just cleaning up and throwing some rust treatment spray on it. The left side of that pictures looks like it has a big hole in it and is only going to get worse until the cancer is cut out and new clean metal replaced. So YES some cars will need 1600 dollars worth of work done esp if its done by a shop! Sure it can be done for less if its a job people can do on their own. Take a picute of your car a year from now I'll bet it will be worse than it is now.......
Now here is a real link that you know shows some pictures how to properly fix rusted rocker panels. Yes this car needed quite a bit of work but I'd bet my entire bank account it will last much much longer than the half-as$ed job you have done on yours!
http://www.autobody101.com/forums/viewtopic.php?t=13467
