If you picked up an iPhone 5, but skipped out on the AppleCare+, you can still purchase it at an Apple retail location. Good news if you have a last-minute change of heart, or if you bought directly from one of the carriers (rather than Apple themselves).
Purchasing AppleCare+ will give you an additional two years of coverage from the date that you purchase the device. It will also cover accidental damage up to two times at $50 bucks per incident. This means if you drop the iPhone and the screen cracks, you can have it repaired.
If the iPhone is broken they will either give you a new one, repair it or exchange it for a working unit that they say is “new or equivalent to new in both performance and reliability” which basically means a refurb.