Boats priced at $700 usually have some significant issues, which is why they are priced so low. The threads linked above will give you a good idea of what to look for when you inspect it. If it has significant issues (soft floors, transom etc.), then you really have a restoration project on your hands (figure $2-$4k in parts, plus 200 plus hours in work).
Having said that, you might get lucky, and find that this is in excellent condition....