Older Caravans

So, having ordered a brand new caravan yet being let down twice on our delivery date, we have decided to cancel our Order and look around for an older caravan to see us through until we get a bigger tow car.  As such we need one around or under 900kg really and so are limited.  We have looked at two today.  One 22 years old for £900 and very light the other 12 years old and £1600.  The older one has signs of damp around the door  and the less older one the owner was honest enough to point out damp on one of the side panels.  My question is, for this sort of money, are we going to get a caravan without any damp and is it such a big deal.  We have no health/breathing issues and have both previously camped.  An older caravan would give us the opportunity to confirm caravanning is for us (and our dog) and just wondered what those who have experienced older caravans thought as I have no caravan knowlege.