The question I ask is, How cheap? What price range are you looking?
When I was looking for mine I found an 05 GT for under 11K. The miles were almost at 100K, but it looked decent, obviously probably not a good buy though. I did see a few 05 GTs in the 13-15K range that looked really good, but agian depending on your price range you could go newer. I just got my 07 GT, bone stock with 28000 miles for 18K (thats a disadvantage to Cali, the dealers will fight to the death to not take money off a sale, but they were asking 23K, and it was the color and options I wanted).
Also if your a california resisdent be careful about buying AND registering a vehicle in your name out of state (esp. nevada), they will come after you to try get their money. They hounded me for a minute when I first registered a car in Cali and still had one registered in my name in PA, and I'm not a resident.