Material cost should be about $60-$80, but the real question is the labor. Realistically it should not run more than a day's labor at a shop (so maybe $400-$500) if the interior is completely out, but that could always change depending on what they find once they start, such as more rust inside the frame, etc. If you are not working on a big dollar resto, this would definitely be a good time to work on your skills. The majority of the work will be hidden unless you want a true show car where people will be crawling underneath to look. A friend of mine and I did my L/F in a weekend, him with moderate welding experience and me with absolutely none. Another problem could be finding a shop that will take on a project this size. They might quote you $1,000+ just because they don't need the work, but will make big $$ if they do it.