Sketch Vector Design App $31.99 ($20 off) OS X
This was posted 10 months 4 days ago, and might be an out-dated deal
I use this Mac app and can't recommend it enough if you do UI, Icon or mockup work.
Also another deal, an unusual "web building" app called Salt is now Free. Never used it before though. http://itunes.apple.com/au/app/salt/id489690506