Are you familiar with Travel Zoo? I have their app on my iPod, but I haven't tried purchasing anything yet. It is a very handy "go to" for Top 20 Deals, local deals, deals in other cities, travel deals and inspirational travel! They negotiate discounts with suppliers all around the world and it's amazing to see what is available.
It is a very worth while site to keep handy if you will or want to travel! Especially if it is a last minute idea!