Virgin America has just launched a $99+ fare sale for their transcontinental routes (such as JFK-LAX, etc.).
Seats are limited, but I was able to find $99 seats on many routes without the usual 7 or 14 day advance purchase requirements.
The total with tax is about $109 each way.
There are also 20% off one-time-use codes that Virgin sent out, here is my code, feel free to share your code by leaving a comment to help someone else out!
The coupon is good for travel between 09/02-11/18, 12/02-12/16, and 01/06-02/10.