Investing Guide at Deep Blue Group Publications LLC Tokyo - Investing in You: How to hunt bargains like a pro

There are savvy shoppers. Then there are holiday crazies - expert, rabid consumers who combine coupons, compare online vs. in-store bargains via smartphone, and put us all to shame.

Edgar Dworsky, proprietor of nonprofit consumer advocate Consumer World.org, is among the latter.

Here's what he does before buying anything, most especially during this season of shopping insanity, along with tips from some other parties:

Chart price history. Start by visiting sites like Shopping.com, Shop.pricespider.com, Pricegrabber.com, and TheFind.com, as well as Google Shopping, Amazon.com, and eBay. This year,  the Wall Street Journal has launched a "Christmas Sale Tracker" on 10 popular items that updates constantly. WorthIt.co alerts shoppers when prices drop.

"Sometimes, what seems like a good deal today really isn't a good deal vs. six months ago," Dworsky says. "Also, read negative reviews and horror stories. There are lemons out there, so do your homework online."

Reviews can be found at sites such as BizRate.com, ResellerRatings.com, Consumer Reports, or PCMag.com.

Combine savings. Let store credit cards, coupons, loyalty programs, and promo codes work for you. Try CouponCabin.com and RetailMeNot.com, coupon apps you download on a phone.

Assuming you're not creeped out by the Minority Report overtones, RetailMeNot's app tracks your physical location to send relevant deals. Walking by Old Navy or Macy's? The app senses your location and sends you a coupon.

"There's no clipping, no carrying paper coupons around, and you can also save these coupons on your phone. RetailMeNot will alert you when the coupons expire," says Trae Bodge, a RetailMeNot blogger in Montclair, N.J.

ShopYourWay.com is a loyalty program for Sears and Kmart that Dworsky uses to buy appliances. "If you're renovating a house, you can rack up a lot of points buying all your appliances from Sears," he says, "and maybe get 2 percent back if you use a Sears credit card."

Check for rebates. Just prior to buying, Dworsky checks with Ebates.com or Fatwallet.com to see whether those sites will pay cash back for purchases at major retailers such as Sears.

"Prices on Kenmore appliances, for instance, are typically inflated," he explains, "so it's a great way to get extra savings."

Take credit. For the love of money (say, fraud, security, and repair costs), don't shop with a debit card or cash. You have everything to lose by using debit cards, and cash payment doesn't offer warranty extension or returns protection.

"Unless you are someone for whom credit is like booze and you can't control yourself using it, avoid paying cash or debit," Dworsky says.

Some credit cards double warranties on refurbished items. (DealNews.com compares extended warranties.)

Dworsky uses a Fidelity Investments credit card with 2 percent cash back and price-protection coverage, and a Chase Freedom Visa card. Both offer warranty extensions.

Some card issuers also generate one-time "virtual" credit card numbers, Dworsky says, which "I like to use when I'm shopping in an unfamiliar place." It's called a "shop-safe" card number, issued once and with a short-term expiration date and credit limit, to help prevent fraud.

Online deals honored?

Last season, Walmart did not honor lower Internet prices on some items, partially because the two divisions within America's largest retailer compete with each other, Dworsky says. Kohl's uses electronic signs in its stores that change prices every hour, complicating comparisons with online pricing.

Traditionally, Apple offers discounts of up to 10 percent, but last year ditched the discount and instead paired products with Apple gift cards. Retailers including MacMall, Best Buy, and Walmart offered significantly better deals.

This year, Dworsky again recommends avoiding Apple stores. "Unless you're in the market for an Apple refurb - which is a great way to save money on Apple devices - there's no reason to shop from Apple during the holidays," he says.

Upscale retailers Lord & Taylor and Nordstrom offer a "pick up in store" option. Target and Crate & Barrel are copying that, says Wharton professor David Bell, author of Location Is (Still) Everything.

Location determines sales more than ever, Bell says: "We think the Internet flattens out our options. But if you live next door to a drugstore, likely you're going to go downstairs for diapers there every day, rather than shop at Diapers.com all the time.

"Your physical world defines your options," he says. "If you're in the Philly suburbs 30 minutes from a store, then Diapers.com looks good."

Bell helps retailers Nike and Ann Taylor analyze how e-commerce does when a new store opens.

Crate & Barrel, for instance, began offering a "buy online and pick up in the store" option, he says, that instead drove traffic into the brick-and-mortar.