Actually, the Prius was and is still unique enough for any "premium", although I feel I got a pretty good deal on both mine. The reason - I traded a Chrysler 300M for my Prius. The Prius has more front seat headroom, just as much front seat legroom, MORE rear seat legroom, and the hatchback design gives it a versatility that you don't find any many other cars. Granted, I can't haul a sofa in the back, but I have no trouble toting around two labrador retrievers, or some smaller furniture, or even a lawnmower. Add to that I have spent $0 on any maintenance outside of oil changes, and it's all the better.
I know I was filling the tank of my 300M weekly, and I fill my Prius once every other week, with half the gas the 300M took. People say the battery will cost when it has to be replaced, but it's got a 10 year, 100,000 mile warranty on it. I do plan on keeping the car...well, I may give it to my daughter in another 3 years. All I know is that without changing my driving habits one bit, I am now getting 45 mpg on average. If I drive with a lighter foot and anticipate stoplights better (which I have done in an experiment) I had no problem getting a 50mpg average on a tank of gas. I also get a $100 a year gift card from work for my "ozone reduction" efforts, plus there are more and more places in my area where alternative fuel vehicles are getting a close in parking spot.