Just happened to notice that all three Sony Readers are on sale this week for the lowest prices ever.
The PRS-300 is selling for just $149 from Amazon.com and the PRS-600 is selling for as low as $249. The 7-inch, wireless Daily Edition is also on sale for $349.
Of the 3, the PRS-300 is probably the best deal overall. Under $150 is a huge price point to hit for any ereader.
Update: Just ran a search and found that the PRS-300 is even cheaper at
Buy.com at just $139.95 with free shipping.