With such short notice, it'll be hard to find something for less than $500.... booking at the last minute is almost never a good deal!

Both Alaska Airlines (which can be cheap if you book a week out,) and Site59, which only sells packages, have pretty decent prices for that kind of thing... site59 specializes in last-minute travel, and sometimes has good prices, but you'll have to book a hotel as well as an air ticket.

This would probably also be a good time to try priceline, to see if any airlines really want to unload an unsold seat.