Instruction: Answer the given question using the supporting document.

Input:
Question: why is the SD 870 IS so expensive???? Why is this camera selling at $589, when it is 3+ years old?
Document: The Canon Powershot SD 870 take very high quality pictures at a very fast speed, the wide angle allows you to take pictures closer than other cameras. I you are looking for one digital camera this one is the one you should buy, it is simply a 5 stars camera!
I bought this for my mom.She is not a camera person, but she can handle this camera easily with it's big 3" Screen, wide angle, and image stabilization!Love this camera!
Also - We picked up a very nice camera case from Fry's made by LowePro for $9.99 - I'd recommend you get your camera 1st, then go shop in a local store for the case; the Canon carrying case for $40 just seemed too expensive.
Great point and shoot camera. Good quality shots with enough extra features to keep the average photographer very happy. A bit more expensive than similar models out there but I think it is money well spent for the sleek design and ease of use. Recommended .
This is a very nice camera. Pictures taken in the daylight look excellent. Still have some problems with pictures taken in the dark (with the flash), but I have read some reviews about tuning the ISO to fix this. Apart from that the product is excellent.
Love this camera, it replaced a Sony Cybershot and it's completely lived up to my expectations. I'm certainly nothing more than a casual user, typically I use it for real estate photos so the wide-angle and image stabilization have been handy. I imagine they'd be helpful to just about anyone who's the same as I am ... someone who doesn't need lots of bells and whistles. I've been very happy with it.
I'm a novice when it comes to photography, but I was really impressed with this camera/video recorder when I saw the quality of pictures and video it produced. And just because it's small doesn't mean you can't add to it. I actually made a diffuser out of bubble wrap to fit over the lens, and it's amazing how much more warm and full the pictures are (for up close portraits that is). This camera is compact, yet powerful.
I'm a "point-n-click" guy. This camera is GREAT. The image quality is superb, motion picture capture is great, software for PC reviewing is great. I just wish that Canon had included a 2GB extreme III memory card with the purchase. The wimpy memory card that comes with the camera took 5 picture + 60 seconds of video, then was full - geez.
Answer: out of production, but still in demand i assume.  it seemed one of those rare "stand out" models in an otherwise so-so lineup.  so i guess it's priced like a collector's item.  mine has since failed, and i'd replace it with same -- IF it were still available at original price.