I just picked up an Antminer S1 on ebay for the cheapest price I could find (including shipping).  At least for a short time, it will give a little boost to my diminishing bitcoin earnings.  Also not expecting to make ROI, hopefully somewhere above 60% ROI for the total amount I have invested in various bitcoin mining solutions.   You might also consider something more efficient like the Rockminer R3 Box 450-500G, although that pushes you up to about $600.

http://shop.rockminer.com/goods.php?id=41