I seem to remember checking out the cost differences between hybrids and similiar non-hybrids a while back. At that point, the cost savings in fuel didn't come even slightly close to making up for the cost difference between the cars.
Here's a current example:
Ford Escape XLS MSRP: $19K Best MPG 28
Ford Escape H MSRP: $26.5K Best MPG 34
Difference of $7,500. Over 5 years that's $1,500/year.
Using 12K as an average mile/year that equates to:
Escape XLS: 429 Gallons
Escape H: 353 Gallons
At $4 a gallon (we'll go on the high side), that's a difference of $304 in the Hybrid's favor. Over 5 years (I seem to remember this was about average ownership length for most cars?) that equates to $1,520.
Let's assume the person owns the car for 10 years and that (for the sake of argument) the battery is not an issue during this time. Assuming gas prices don't skyrocket (though even at $5/gallon the math doesn't change much), that's $3,040 over 10 years. Still not even half of the price difference between the two cars.
Of course this is an SUV, so that skews things somewhat. So what about the Camry?
Camry SE MSRP: $22,390 Worst MPG 21
Camry H MSRP: $25,350 Worst MPG 33
$2,960 difference between the two. I went with worst MPG above because there is so little difference between the Camry's citi and highway that it would skew the results.
Using the same figures above, we have a difference of 207 Gallons/year or $828/year @ $4/gallon. It only takes 3 and a half years to make up the difference here. Much more attractive...
This one is difficult as it's hard to compare the two. The H has 192 HP whereas the regular Camry either has 268 or 158. Further, the number of possible regular Camrys makes it difficult to compare the two as well. I used the SE, but if you compare it to the XLE the two are almost the same in cost.
Now, how about the Prius vs the Yaris?
Yaris Sedan S MSRP: $13,725 City MPG 29
Prius Base MSRP: $21,100 City MGP 45
Difference of $7,375 between the two.
Now this one is interesting. I'm using City again because the Prius's MPG ratings are so close. Using the same math:
Yaris: 414 Gallons/year
Prius: 267 Gallons/year
$588/year difference @ $4/Gallon. It would take 12 years to make up the difference here. Ouch.
I understand that there can be other reasons to go with the Hybrids than saving money, just an interesting comparison.