Which is the most costly car in world?

Its very difficult to say it because there are many cars to be made still and they maybe more costly. The future cars can (if there are any like flying cars) cost up to many crores!

We can't say.

ANSWER:

The 1931 Bugatti Royale Kellner Coupe was sold for $8,700,000 in 1987.

but that was not in the market and it is not street legal

Bugatti Veyron $1,700,000. this is the most expensive, street legal and on the market car