Yeah, you read that title correctly. Someone must have messed up somewhere because the Sony PRS-600 is selling for just $100 from Borders.com with free shipping, and I took the picture to prove it.
I find it hard to believe that this isn't some kind of error.
Update: Placed an order and it seemed to go through fine. After the order it said they'd send a confirmation email of order status in 24-48 hours so I'll update then.
2nd Update: Borders now has both listed at $199, making it look even more like the $100 price was an error. Waiting for confirmation. The mystery deepens.