Mike,
There is a cobras for sale section here in this forum (go to Quick Forum Hop) or go to
http://www.cobracountry.com/cobrasforsale.html.
You should also buy the cobra buying guide or search some threads here that chronicle a specific make of cobra. The more homework you do here on your own, the more willing this community will be to help you address more specific issues pertaining to a car you might consider for purchase.
There are lots of cobras to look at, so look at the listings and then go from there,
good luck, take your time and don't settle for something that's got less than you're looking for. Pay for quality and you won't regret it and you won't lose much on resale.