Here's what I know about Kindles:
- The Fire is the most expensive because it's the only one with a color screen. It's an entry level tablet that can be used for listening to audio, watching video and surfing the web. The others have gray and black e-ink screens and are dedicated ebook readers. All but the basic model can play audio files, but their functionality past that is limited. If you just want to read ebooks, the basic Kindle 4 will do.
- My district piloted the Kindle Fire to possibly consider its use as a tablet. The results of the pilot discovered that for use as a tablet, it was limiting. The Fire for surfing the web, checking email and as an e-reader, was great. However, it was limited to only wi-fi connection and if taken outside and used in sunlight, the screen was hard to see.
- I have a Kindle 2 (White with keyboard, using e-ink, 3G connectivity) & my husband has the Kindle 3g w/keyboard, and have no complaints using as an e-reader. When used in sunlight, no problem. I realize you want wi-fi connection, but still the e-ink is easy to see. Internet connectivity is limited on these models, however. I haven't checked out the Kindle touch screen or Kindle wi-fi only w/e-ink.
Conclusion: If you are only wanting to use it as an e-reader with wi-fi connection, the Kindle may be the way to go. Check with Amazon and see if you can pilot a few of them. That's what we did with the Fire. Then after our trial period of one month, we sent them back in their original packaging.
Hope that helps. Good luck on your search.
Anna - I suggest reaching out to community memeber susangauthier. She purchased several e-readers for the school library- she can give you her feedback and she can tell you what devices she liked and worked well for her.
Good luck - and keep us posted if you get your grant and what you decided to do.
I've had the cheapest new version (the Kindle 4, with buttons, not touch), and, for my own use, I totally love it. It's a great basic reading device: It's small light, totally easy to use, has a high contrast screen that does well in a wide range of light conditions, and is cheap enough if it breaks it isn't the end of the world. However, it's not a good choice if you want to take note given the need to navigate the on screen keyboard with arrow buttons.