I saw the following question on Yahoo Answers and I thought I could answer it here.
What exactly do hybrids run on? Are they practical? Do they save you money in the long run or are there some unforseen expenses, say with parts and repairs, that would eat up those "savings"? What's a good model and why?
Hybrids run on gas and electricity. The gas, of course, you know about. Large battery packs, usually stored near the back of the hybrid, power the electric motor. The battery gets its power from regenerative braking and the gas engine. (Find out more by perusing the types of hybrid cars).
They are a practical choice but, if you're willing to go small, a compact will save you the most money in the long run. But if you do buy a hybrid, according to a recent Intellichoice study, you will save money eventually. Its tough to overcome the initial premium cost, but after an average of five years, you will make up the difference.
The best way to save money is to look into the federal tax credit, followed by any local tax credits (PA offers a rebate, for instance). You may also be able to get solo access to a HOV lane, but again, that depends on which state you live in. Some other local perks include free parking.
Hybrid engines have been reputed to be very reliable. The only 'hidden cost' is the battery pack. If it goes, you could be looking at thousands to replace it. But, automakers guarantee the battery pack for 8 or 10 years (again, depends on which state you're in), which means they will pay for the replacement if you need one.
You can actually save money on maintenance, since you won't have to replace the brakes or oil as often. The brakes last longer because the regenerative braking takes some of the load.
As for which model is best for you? I couldn't say without talking to you directly. You can look over my list of hybrid cars.
If you're looking for the best hybrid, the Prius is almost synonymous with hybrid. You can also get a good deal on it right now as Toyota is trying to increase sales. But if you're looking to buy a hybrid, don't want the weird shape, but still want to save on gas, there's the Civic or the Camry Hybrid. The Accord hybrid was designed for performance, so I'm assuming you don't want that one. That's because very few did and the Accord was subsequently retired.
If its a hybrid SUV you want, you could look at the Ford Escape or the Toyota Highlander Hybrid. If you want more luxury, then the Mariner Hybrid could be the one for you.
If money is no object, you might look into the Lexus hybrid line-up.
The Saturn Vue hybrid is a mild hybrid and, while you may pay less up front for it, you also get less. A mild hybrid has both the electric motor and the gas motor. But, unlike a full hybrid, the electric motor can't move the car on its own. A full hybrid allows you to get up to speed (30 mph, depending on the model) before the gas engine kicks in. A mild hybrid engine has the electric motor assist the gas motor to increase its fuel economy.