Prius maintaining incredible value

I recently checked out prices for certified pre-owned Toyota Prius', and was astonished by what I found. Not only are prices high on more recent models, but even four year old Prius' are maintaining nearly all of their original value.

To clarify a bit, I'm not looking for a new car, and we already have a Prius. However we've received a number of buyback offers from various dealers in the area and I was curious what a dealer certified pre-owned Prius actually goes for.

So how much are you looking at for a certified pre-owned Prius? Well assuming you can even find one - there are only 12 in a one hundred mile radius of our area, and 5 within twenty-five miles - anywhere from $20,000 to $29,000 (obviously prices depend on your area).

As an example I found the same year Prius we currently own with the same options (not difficult as that year only had three packages; none, esp, satnav):

2004 Toyota Prius (with esp)
Miles: 38,000
Price: $20,000

And what did we pay for it brand new, four years ago, right off the lot with no miles? $24,000

Even crazier:

2005 Toyota Prius (with esp)
Miles: 45,000
Price: $23,000

Obviously we wouldn't get anywhere near this in a buyback, but regardless the car is holding incredible value. And this on top of the gas savings... wow.

So what about the $29,000 Prius:

2008 Toyota Prius
Miles: 9,000
Price: $29,000

Well even used it seems to be going for over MSRP.

While this is great for us, already owning a Prius, it must be difficult to find one at a reasonable price.