I'm an avid reader, and it is a must have in my opinion for people like me. I've bought over 10 Kindle books already and it does save me some money. I know it will be good in long term, as I read some review mentioned that on average money saved on buying 70 Kindle books can actually cover the price of the Kindle device. There is a good review on this here:

http://www.speedreaderxreview.com/is-kindle-2-worth-the-price

Unless you want used Kindle, the only "first hand" place and the cheapest place to buy new Kindle is Amazon. You can find someone selling on eBay, but if it is "new" Kindle then it must have price higher than that on Amazon. Those sellers just get the product from Amazon and sell it to people outside the United States (because Amazon only allow orders in the U.S. right now), and they earn the difference.

If you are considering to buy it, read one or two reviews on Amazon customer review and you should have your decision:

http://www.amazon.com/gp/redirect.html?ie=UTF8&location=http%3A%2F%2Fwww.amazon.com%2Freview%2FB00154JDAI%3Fie%3DUTF8%26ref%255F%3Dcm%255Fcr%255Fpr%255Fhelpful%26showViewpoints%3D0&tag=moreinfo-po-20&linkCode=ur2&camp=1789&creative=390957

Hope it helps.