This is a great question, and for that matter great answers. My ideas are this:
When I bought my first vette I was 18 years old. It was a 1958. BUT! It was only $1500 back then. (I’m an old guy of 49). Presently I have a 88 C-4 rag top that I love. But, it is seen by me to be a toy, and only a toy. I do not rely on the car as a daily driver. I bought the car for cash, and maintain the car with “my funds” or the “vette” fund. To me this has to be liquid cash that is not needed for any other reasons. IE: Kids collage funds, retirement, investments, home repairs etc. In short, the Vette comes last, or near last in home finance. * Note: This is important along the wife/husband relations. After all, if your wife (for this of us that have them) is happy with the car your life is far more pleasant in owning one. (no, she does not have to like it, but better is she does).
I won’t go into income levels, but safe to say I have a very decent income. Notice I bought an older car, and did not invest in a new one or a more exotic car. Reason is, I could pay for the car with a check, and not even think about it. No offense, but if you have to ask the question about cost, it may not be time to buy. But, only you know that. (after all, you have to have a car of some sort right?) I’d just hate for my primary means of transport to be the vette. (sorry, but the Toyota Land Cruiser is bullet proof and I drive 99% of the time).
Good luck, and when you do decide to buy one be sure to have tons of fun!