Besides the price going back down, they have also re-instated the $50 trade-in program (Until Dec. 31):
http://store.sony.com/webapp/wcs/sto...&cmsId=tradeup
(It's on the bottom right of the page.)
If you trade in an older reader, you can buy the PRS-T1 for $79. I am seriously considering trading in my 300.