My local car dealer offers me 0% interest for 6 years on a $40,000 truck.Alternatively, I get cash back incentives of $4,000 if I arrange for my own financing.Which alternative is better if my credit union offers me a 2.99% car loan rate?

If I were to take the no interest option, my monthly payments would simply be $40000 / 72 months or $555.56.

On the other hand, if I were to arrange my own financing, I would only pay $36,000 for the truck and my payments would be calculated as follows.