93 cobras are pretty rare and will be pretty pricey. They are awesome cars though.
94-95 are the cheapest cobras, your best bet if price is really important. Fun cars too. (Pushrod=unlimited potential in a newer package that can be made to go fast and turn)
96-98s are my favorites, they are right in the middle of the price range, are faster than either of the afforementioned cars from the factory. The best for daily driving if you ask me.
99 and 01 Cobras are when they swithed to IRS and upped the powerplants output slightly to like 325 crank hp I think(dont quote me)
Of course in 2000 the only Cobra made was the 00R, only 300 made. You can find a very few for sale but they are big bucks.
03-04 Cobras are just awesome in my opinion and they are whats really hot on the streets right now, you can find some pretty killer deals if you just look. Just beware of early 03s because they had/have a problem with the heads.
And now youve got the 07 coming out...and you know what thats like.