It's a first gen roadster, I believe, so it's a decade old. If it's worth six figures, it's for its historical value (and if it's ever retrieved from Mars it'll be worth FAR more in that regard after this stunt).

Has the world gone mad that we’re worrying about the six-figure cost of a dummy payload on the test launch of a nine-figure rocket?

The cost of the second hand Tesla is nothing compared to the PR value of doing this.

That's cheap though, a sattelite that size costs millions if not tens of millions.

Although I guess you could argue this one does too, given that it's not from the production line, probably hand-built.

You are missing the point. The point he is making is that he is actually taken some risk or putting something that is dear to him, in jeopardy.

If the mission is successful, do they recover the car? Or will it be released into orbit? And if that, will it eventually burn up?

Incentive for BFS to do something spectacular on its maiden voyage.

It will orbit the sun for hundreds of millions of years

... Until it is recovered by space pirates and sold as a historic artifact....

Imagine a human like alien civilisation discovering the car. They would be like we found the chariot of God.

Great question.

It doesn't cost them 6 figures.

Potentially did when he built it. Wasn't this the very first fully assembled one ever built?