I have the Walmart, Amazon, and target iPhone apps. I regularly search for deals since I’m trying to build up my brick collection (just came out of dark ages in October 2014). Lego shop at home had it listed for $40, so I knew this was a good deal. Too bad it sold out.
Forgot to mention I also read brickset’s shopping guide, lego s@h sales, brickpicker, slickdeals, Craigslist, eurobricks, etc etc. I happened to have found this deal on my own though. 🙂