Jetbook lite might be the best option as a tradeoff for cost and the ability to play MP3's. They are a great product.
http://www.ectaco.com/main.jsp?do=pr...fid=29532#spec
The best way to buy one of these (sub US$99) is from the US, via online stores or ebay. They use 4 AA batteries for 23 hours reading.
Do try and avoid the cheap ereaders as mentioned in my post above.