re: When should you buy a car with cash vs financing at 0%?

I don't know about auto financing specifically, but in general 0% financing for X amount of time generally means that you actually pay all the interest as soon as that X amount of time is up. For example if you do 0% financing for 4 years but it's a 5 year loan with 2.99% interest then the entirety of that 5 years and 2.99% interest is paid during the 5th year. It's all a marketing gimmick. Now, you can pay the car off by the 4th year and as long as there are no penalties it works out as actual 0%.

Also, as said with 0% loans they usually don't give any rebates. So know what you are getting into.

Yes, I mean investing the money for 47 months and then paying the loan off on the 48th month would work out as you planned.