Hi matey, good question but you will find that it will depend on how much you are willing to pay and what condition the car is in, there doesn't seem to be any hard and fast rules on the price of mk1s but they are steadily becoming more and more expensive, if you find the right car and are willing to pay the price asked then I'd suggest that you go for it.
Best to check out places like autotrader or the Golf+ website in the classifieds to get an idea of how much they are going for, I'd be surprised if you can find a campaign though. Happy hunting
