Ok so using that car as an example (although it's automatic so never came up in any of my searches). Currently available for ~$17K new (after $4000 incentive) which means it only depreciated $6000 in its first 57000 miles, or ~10.5c per mile with presumably very little maintainance. If I were to run that until it dies (let's say 200k miles it would cost me about 5.5c per mile, so about $7000 less but I'd need a whole bunch of maintenance, at least 3 sets of tires, brakes etc. Maybe a savings of $3000 over not driving a new car every 3 years or if I just bought it new it would cost 8.5c per mile about $4000 extra.
So it's definitely cheaper to buy used but not really a very significant saving considering the risk of getting a lemon or something that has been driven like a getaway car and might never make it to 200K.
I've read a lot of people say the sweet spot is 2-3 years but I'm just not seeing it. BTW I'm not trying to justify a new car, I'm trying to justify a used car but I'm struggling to find anything that I'd regards as a good deal.
The depreciation hit on 2 to 3 year old cars was so large that it essentially amounted to an inefficiency in the market, which has largely been traded away as people have continually pointed out that 2-3 years is still basically new. The last car we bought, we bought new because the depreciation was pretty much straight line over the first 5 or 6 years, at which point it started to slow down considerably. That car before that, the depreciation looked like what everybody claimed, very steep depreciation immediately, then relatively steady depreciation for several years before it slows down, so we got huge savings by buying a 6 month old program car versus buying new.
In hindsight, for our last car, we should have just bought the 5 or 6 year old car, but we already had one 5 year old car, and were trying to stagger the ages to try to evenly space future car purchases. That really wasn't a good reason to drive so much of our decision, and we should have purchased the older car and planned on trading in more often.
But all that to say, if you're buying a car say 4 or less years old, there's not that much difference and getting a good deal on a new car is probably better than retail price on a three year old car, if you're just looking at depreciation and cost per mile. If you really want to save, you need to move out to or past that 5 or 6 year mark.