I'll push the Miata. $10K buys you a decent one and you will be able to sell it for $9500. Pay now, or pay later...

RWD, 'beginner power', forgiving, great brakes, great support...it's all there. The best thing is that it will make you a better racer. You will always be 'in' a race so you will learn racecraft. You have to focus on momentum and you will pay dearly when you make a mistake. You also have a platform to convert to ITA or ITS should you desire to do so.

....and depending on where you are, you will have a multitude of run groups to double up if you are sharing the car.