TL;DR: There is no good reason to buy this car.
I drove a 2014 Prius C with the "Two" trim package. Price: $11,000 +TTP.
The "C" in "Prius C" stands for "city". Trust me, you don't want to drive it on the highway, not even for the 2 miles I did on my test drive. It has no guts on the highway, and pressing harder on the pedal accomplishes nothing.
The C rides on the same platform as the Toyota Echo, 1G Yaris, Scion xA, and 1G Scion xB. I had an xB, and the primary reason I got rid of it was that it wasn't a good car on the highway. Neither is the Prius C, but the gas pedal and CVT are programmed 100% towards MPG. Unlike my Scion, you can't beat it like a rented mule, and downshift to 3rd to get more go.
The market for this car is urban commuters. It might be okay for that, but here's my issue. If you have a short, urban commute, you aren't piling miles on your car. And since you aren't, the difference between the 50mpg of the C vs. 35mpg that far more interesting cars get just doesn't amount to much cash.
(Math time: at 10,000 miles a year, and assuming $3 gas, a 50mpg car will cost $600 in fuel. A 35mpg car will cost $850 in fuel. That amounts to about $20 month.)
I can think of half a dozen commuters that cost under $11k, get 35mpg, and are a lot better to drive. First thought would be a Mazda2.
If you really, really want that super-duper hybrid MPG, you'd be far better off buying a regular Prius that's a couple years older and has 20k more miles for the same $11k. It's a better car by every single metric, except for parking in tiny spaces.
Regardless, you don't want a Prius C.