You're wrong.
0% financing costs less, and so does any interest rate that is less than inflation. If inflation is 3% and your interest rate is 2%, it's cheaper to finance at 2% than it is to pay cash.
Assume the following:
- Inflation of 3%
- You have $50,000 cash
- You want to buy a $50,000 vehicle
At 0% interest financing over 60 months, the discounted present value of the payments, factoring in inflation, is substantially LESS than $50,000.
At 3% interest financing over 60 months, the discounted present value of the payments, factoring in inflation, is $50,000.
Think about it this way. If someone asked you in 1950 to pay them $10,000 either immediately or in 2017, which would you pick? $10,000 in 1950 was a substantial amount of money.
$10,000 in 2017 is negligible. The same principle applies to shorter durations of time.