My opinion: all the rust I see in those pictures is on parts that ANYONE can replace. Even the subframe is something you can replace with some common tools. And I'm not saying those parts have to be replaced, rather looking at if from a worst case scenario, you can find used rust free parts easily and swap. It's when you have rust that requires a torch to cut out an a paint job afterwards that you have to worry about the cost. Go w/the rust encapsulator Nick mentioned and enjoy the car while you keep an eye out for bargain (rust free) parts.