These credit cards, freebies, apps and tweets will tell you when to strike for the best deals. July 2, 2012 Time a discount With the prices of some products changing moment to moment and Web site to Web site, scoring the best deal can require precise timing. But there are tools that will let you know when to click “buy” and when to wait a few days. SEE ALSO: How to Score Even More DealsDecide.com tracks when electronics, such as game consoles, phones and TVs, are likely to drop in price, based on new product launches and other prices posted across the Web. Users save an average of $87 on a purchase, according to the site. Download Decide’s app (Android, iPad, iPhone) to set price alerts and compare the cost of gadgets at nearby retailers. Plug your itinerary into the Bing Price Predictor for advice on whether to buy plane tickets or wait until fares drop further. The tool saves customers about $50 per round-trip transaction, according to Bing. Advertisement After buying airfare, enter your itinerary and the amount you paid for the tickets into Yapta. The site will let you know if the price drops enough in the following weeks to qualify you for a refund, voucher or flight credit. For airlines that charge a fee to change or cancel tickets (often $75 to $150), the drop must be sufficient to overcome the expense. When you reserve one of Tingo.com’s thousands of “Money Back” hotel rooms, you’re automatically rebooked at a cheaper rate if the price drops. Options range from the Wynn in Las Vegas and Waldorf-Astoria in New York City to various Hiltons, Marriotts and other chain hotels. Social media Interact with your favorite companies, and they’ll reward you. Advertisement Friending or following companies can unlock coupons, earn you freebies and alert you to time-sensitive deals the moment they surface. Getting deals may require you to tweet “at” the company or “like” a page, so make sure you don’t mind having your profile co-opted for advertising purposes. Follow Amazon’s suite of deal alerts (@AmazonDeals) on Twitter and Facebook for “Gold Box” discounts—the site’s daily flash deals—and other bargains. Pinpoint your favorite Amazon section with dedicated feeds, including @AmazonMP3 (recent offering: Of Monsters and Men’s debut album, My Head Is An Animal, for $2.99); @Amazon_grocery (recent offering: 35% off Kashi cereal); and @Amazontechdeals (recent offering: 20% off all Rosetta Stone language-learning software). Couponers can follow Retailmenot and CouponSherpa for a selection of the best coupons that day (having the offerings curated by Twitter helps narrow down the choices). For travel, follow your favorite airline on Twitter or Facebook—JetBlue Cheeps and Virgin America are two favorites—or use a travel site such as Airfare watchdog or Farecompare for flash sales and price-drop alerts. Free stuff Advertisement Put away your wallet. These goodies don’t cost a cent. Take a class. Saylor.org and University of the People offer dozens of free, high-quality classes. Or go straight to top-notch schools. Harvard, MIT and Stanford, to name a few, offer free online courses. Many others provide free course material online. It’s not for credit, but you take the same classes that enrolled students take. Visit the schools’ Web sites for more information. Snag some tunes. Amazon’s Artists on the Rise is a monthly collection of free MP3s from new musicians. The latest picks include The Alabama Shakes’ “Hold On.” Find a classic e-book. Project Gutenberg has more than 39,000 free e-books available for Kindle, Android and Apple products. Even booksellers Amazon and Barnes & Noble offer free e-books. Advertisement CREDIT CARDS With these choices, your plastic pays you back. Cash back. Earn 5% cash back on up to $1,500 spent on bonus categories, such as gas stations and restaurants, that change each quarter and 1% on all other spending with the no-annual-fee Chase Freedom Visa card. If you max out your purchases on the bonus categories and spend a total of $18,000 a year, your rebate will be $420. Chase is offering a 0% rate on balance transfers and purchases for 15 months. After that, the interest rate will range from 12.99% to 22.99%, depending on your credit score. Rewards. Earn two points on every dollar spent on gas, groceries and utility payments, and one point on all other spending with the Barclaycard Rewards MasterCard. This no-fee card offers a 0% interest rate on purchases and balance transfers for 15 months, then charges 14.99% to 24.99%. Another good choice with a lower interest rate is the PenFed Visa Platinum Rewards card. Balance transfers. The no-fee Citibank Diamond Preferred and Citibank Platinum Select Visa cards offer a 0% introductory rate for 18 months for both purchases and transferred balances (with a 3% balance-transfer fee). After that, the interest rate ranges from 11.99% to 21.99%. You receive 24-hour concierge service with the Diamond Preferred card. Each month, Platinum Select cardholders receive 10% of their purchases as Extra Cash dollars that can be used to lower the price of an item at participating retailers.