I started a new game on 2nd Gear and the material costs for the car I designed was only $223 after R&D was completed, despite the vehicle designer saying the estimated material costs should have been around $1200. I also noticed that there were two luxury sedans on the market for -$1200 and -$1500.
I'm assuming you're playing in Windows? I have tried three computers, all on Linux, and have not been able to duplicate negative numbers or costs being less.
I am playing on a Windows 10 machine
I started a new save, and the material cost estimate is accurate until the production lines are set up and cars start hitting the dealers. I don't see any cars with a negative cost for sale in this save, but I do see some in the show room with a negative material cost
Edit: The material costs bug only shows up for me in the mega menu when I don't have a preset region selected, and if I set production to 1 unit I am charged the correct amount of money for material. I also did end up finding some models for sale at a negative amount, and they are the same models that show a negative material cost in the marque catalog
Was the first save originally from the previous version of the game? You should always start a new save game when the 2nd Gear games get updated. They're not backwards compatible.
If you can send the second save game you made to me, that will be helpful. I can not duplicate the issue on any machine/OS I have.
Seems to be an issue with the Components/Vehicle inflation setting. Disable that, and it should work fine.
I'll have an update out soonish.
Released a hotfix that should resolve this issue. You will need to start a new save game.