Okay so maybe it's not exactly a hack but an AMAZING resource for the best Amazon deals at every minute of the day. Fat Kid Deals is a Twitter account that gets you the hook up on Amazon (and Ebay) deals whether they're flash deals or coupon codes or secret sales.
Warning: they DO flood your Twitter feed with tons of tweets but you can find crazy good deals on legit items.
PLUS, the people that run the account are interactive, funny and take part in current memes and trends. It's a win-win!