One good tip is to shop on the last day of the month and keep them there until midnight. They are always eager for that one last sale to meet their number or blow it out. We’ve done that a couple times and have gotten some great deals.
We bought extended warranties on two cars and both times they paid off big time with major repairs well in excess of the warranty cost. But it’s a complete crap-shoot.
To put it this way, the warranty insurers are betting that you won’t have a major breakdown, and you are betting that you do. Guess who has researched the data more?