Nono, im not saying you paid too much, galvanized is expensive. I bought my metal from metal supermarket too, they charge top dollar but have anything you would ever possibly need. I was just saying that for the amount of metal he needs there are other more cost worthy solutions then to pay top dollar buying new stuff.
From the pictures, it really dosnt look too bad. Start removing the sound detoning as that may be covering more rust. Get the frame rails replaced, holes patched and your good to go, beat on her till she dies.