If you do get a 0% offer, sure. But unless your credit is out of this universe, it won't happen.
Because I bought my car cash, Ford gave me an additional 500 dollars rebate that nobody else got. So that means I would have to earn 500 dollars interest on 20,000 in 5 years for it to be worthwhile to finance, even at 0%. And of course with CD's making 1%, that's not going to happen
I got the credit to use the 0% offers. And don't tell me that you have ALL your money in CD's? NO WAY.
You could make more than $500 over 5 years on 20k. Not to hard really. Look up Vanguard on the 'Net.
Invest some of that money.