IMHO Extended warranties are for those "risk-averse" with more money than sense. These are very high profit items for the seller and for most buyers extended warranties are a waste of a lot of money - that's why there is so much profit in the sale.
+1000.
The dealer will convince you you need it. The most common way is by telling you a story. It's probably a true story! They'll tell you about a guy who came in, and needed a $5,000 repair, and the only thing it cost him was the $100 deductible. Wow, he saved $4,900! He'll even follow it up with telling you how he sees people bringing in cars for extended warranty work every day.
The story the dealer did NOT tell you, is that the vast majority of extended warranty repairs are just a couple hundred bucks (keeping in mind most extended warranties are THOUSANDS), and that expensive repairs are rare. In fact, the house always wins. It's a product the dealer and/or manufacturer sell that they make a profit on. Period. That means that more owners spend less on repairs than the cost of the warranty, than those who do the opposite. Overwhelmingly so. You might get lucky and end up saving a few hundred bucks or even a few thousand (after deducting the cost of the warranty), but statistically, even if you do have repairs under the extended warranty, they will not equal or exceed the amount you paid for the warranty. Be leery of dealers who offer 'free' extended warranties, as they generally have higher asking prices for the cars. (Nothing is free at a dealership. They will get paid.)
As an add to your private seller comment, be prepared for "But that's what they are selling for". To respond to that, ask them if they know of any that have
sold for that price. Often private parties will list a car for what other cars are listed for on Craigslist or even eBay. What they don't realize is, I could list my chainsaw for $100,000. Doesn't mean it's worth it. If a car is on eBay, or on Craigslist, or Carsoup, or even the dealers lot; then that means it
has not sold. Even some of the dealers will use that excuse, "You won't find it any cheaper on any other lot". That does NOT matter. If it's on the lot, it's not sold. That's a lame excuse. Never pay more than book value. For a couple of reasons. 1) If you are financing, typically you will need a bigger down payment and/or will pay a higher interest rate if you are buying above book value. That's because the bank sees that as an additional risk, because you'll be upside down on the car the moment you sign the papers. Then, if you default, the bank is stuck with a car worth far less than you owe. They'll charge a higher interest rate and/or require a steeper down payment in order to protect themselves. 2) Again, you're upside down the moment you sign the papers. Why would you want that? 3) Again, if you are financing and decide, down the road, that you want to trade it in for something else but it is NOT paid off; you will NOT get a good deal on your next car. Sure, the dealer may offer to pay off your vehicle, but they are going to work that into the price of the car; don't worry. Trade ins are one of the ways dealers shuffle money around to make it look like you are getting a good deal. (Like $3000 over blue book trade deals that are always advertised). If you are wanting the best price for your car AND the best price for your trade, it won't happen if your upside down. Likewise if you go the more-work but more-profit route of selling your car (which is what I always do), you won't make anything. Unless you can sucker someone into buying it for above-value, you'll actually lose money. If you owe $12k on a car worth $10k that you sell for $9k, then you'll have to bring the bank $3,000 in ADDITION to the $9,000 you got from the buyer in order to pay off the loan. That, or you can trade it in and pay thousands over what you would have otherwise, because the dealer is going to work that $3k deficit, PLUS their profit margin on your trade, into the price of your car.
Book value for your market should be your maximum price. If you want to pay book, that's fair. But a penny more is a bad idea. If you are buying a car that you just have to have and you absolutely cannot negotiate a price that keeps you from being upside down shortly after purchase, then be prepared to own it for a long time (assuming you are financing). I just had a friend go through that. Didn't like his car, wanted a new one. Wasn't big enough, for one, now that he had kids. But he was upside down! Lost a ton of money trading it in on an SUV. Dealer gladly paid off his loan, but gave him no actual money on the trade and wouldn't budge on the price of his SUV. Cost him thousands. (In fact, he'd have been better off just to pony up the cash and pay down the deficit, then sell the car outright and pay it off. Would've cost him less!)