You want cheap, or do you want to win? I guess the real question I should ask is, what do you intend to do with it?
Is it for a challenge? or are you rounding out your garage?
If you didn't sell it you should have the cheapest car, the Toyota MR-S
For cheap you can get an MR-S. But by the time you get it competitive you could have bought some of the cars below.
There is also the turbo MR-2. It is quick and quite agile.
But if you aren't adverse to spending the cash to win, the NSX and the Lotus Esprit are very worthy contenders.
Also the Opel Speedster, though it requires an infusion of power adding parts, and the Lotus Elise are contenders a little farther down the price scale.