Amazon offers the BioShock Ultimate Rapture Edition (Xbox 360) for $19.99 with free shipping on orders over $25. PS3 version is also on sale for the same price.

What makes this deal hot:
You save a total of $10 off of the retail list price. That's the lowest price we could find currently. No tax in most states. This deal includes BioShock, BioShock 2 and add-on content for both games valued at more than $40