1971 dodge dart swinger

I wouldn't pay more then 300 for it. (and that would be to part out the good stuff and crush the shell) Yes it has some good but it has A LOT OF BAD. Unless you are willing to do body work (even if you can do body work it's a lot) it is going to cost BIG bucks to fix that rust and if the frame needs fixing like you indicated it is only gonna be lots more. If you have another one at home spend your money wisely and spend it on that.