Kindle 3, preowned, $35

Cowboom [cowboom.com] offers pre-owned Kindle 3s (6" e-ink screen, keyboard) WiFi for $35.
3G model (used to have a free internet anywhere, not sure whether it is still available) for $70 here [cowboom.com] as a deal of the day.
Both have around +5$ for shipping.

EDIT:
Users report that it goes in/out of stock, so if you are interested and it shows OOS try checking back later.

Copy pasted more info:

Display
The Amazon Kindle Wireless Reading Device's 6" diagonal paper display, is optimized with proprietary wave form and font technology, in a 600 x 800 pixel resolution at 167 ppi, on a 16-level gray scale.

Size in inches
7.5" x 4.8" x 0.335" (190 mm x 123 mm x 8.5 mm).

Kindle's Weight
8.7 ounces (247 grams).

Storage
4GB internal, with about approximately 3GB available for user content.

Battery Life
A single charge will last for up to a month with wireless turned off. If you keep the wireless always on, then it will last for up to 10 days. Your battery life will vary based on wireless usage, such as shopping, the Kindle Store, and downloading content. In a low-coverage area or in EDGE/GPRS-only coverage, wireless usage will consume battery power more quickly.

The Kindle Wireless Reading Device's Charge Time
Your Kindle Fully charges in approximately 4.5 hours. Also supports charging from your computer via the USB 2.0 cable.

Kindle Wireless Reading Wi-Fi Connectivity
The Kindle supports public and private Wi-Fi networks or hotspots that use the 802.11b or 802.11g standard does not connect to enterprise or peer-to-peer Wi-Fi networks
USB Port
USB 2.0 (micro-B connector) for connection to the Kindle U.S. power adapter or optionally to connect to a PC or Macintosh computer.

Kindle Audio
3.5 mm stereo audio jack, rear-mounted stereo speakers.

Content Formats Supported
Kindle (AZW), TXT, PDF, Audible (Audible Enhanced (AA, AAX)), MP3, unprotected MOBI, PRC natively HTML, DOC, JPEG, GIF, PNG, BMP through conversion.