My experiance from looking over the past few months.
Prices over here (uk) seem to vary from £3-5k for something that will run just..... no history and with everything leaking.
Folks seem to ask c. £7k for cars which may have had some history but needs loads doing.
c. £10k is pot luck time.... it should look ok, get it inspected by an expert. Folks seem to have this as a bench mark figure. You could pick up a good car for this amount or a bit less. You could end up with a dog that has been prettied up a bit. Take the advice from people who have owned and run these cars. A good car will feel good. (sorry about that last sentance before you shout....)
>£10k I didn't look at too many cos I couldn't afford them/didn't want to spend that money. Some nice looking cars have been advertised at £17-£24k recently, I haven't tracked what they went for as they were too much for me.
If you are in the market, my advice would be to not wait until the perfect car comes along, because unless you are luckier than me it won't. Get a car that is affordable to you. Bear in mind the cost of turning it into a car you really want. My short ownership has shown me that the 968 is very capable of being a car I really want!
Hope this helps.
Cheers
Oily