When you arrive at your retailer of choice, your smartphone will come in handy. Apps like Foursquare and Facebook Place let you "check in" via smartphone when you arrive at a business. Doing so may earn you a reward. Facebook Places recently offered 20% off at H&M, for example, while Foursquare users got $50 off a $300 purchase at Zales.
Your phone is also a great place to pull up coupons. Apps like Coupon Sherpa and MobiQpons find deals at stores near you. Some stores have their own apps, too. Target and Toys 'R' Us let customers pull up coupons on their mobile phone and scan them in the store.
Facebook users make sure you "like" the retailers you frequent. Most mainstream brands have their own pages by now, but truly social media-savvy companies will have deals. Sometimes you have to click through the tabs or play a game to find them. Old Navy offers a "Barker's Bones" game that has an animated dog dig users up a weekly discount, usually about $10 off a $50 purchase.
Follow the stores you enjoy on Twitter. Pay attention to companies' fast-moving feeds for exclusive sales. JetBlue and United post weekly Twitter-only fare sales, some for as much as half off. Coupon sites such as RetailMeNot and Dealnews also maintain feeds to pass along the latest sales and coupons that come their way.
There's a downside to using social media to get better shopping deals - all your friends know what you're doing. Some of these apps and sites automatically broadcast your actions to your friends and followers, unless you specifically tell them not to. Keep that in mind if you want to keep that present under wraps.