It is the holy grail of coupon clippers: When store sales and manufacturer s coupons align just right, and shoppers can grab certain items for nothing.

Through Feb. 20, for example, CVS shoppers can get Aussie shampoo or conditioner ($3 before $2 in store rewards and a $1 manufacturer s coupon). At Rite Aid, there s Motrin ($3 before a $1 manufacturer s coupon and $2 store rewards).

Grabbing those freebies, however, requires fast reflexes. Consumers have been clipping more coupons in the struggling economy, and that means more competition, says Erin Gifford, the founder of Coupon Cravings. You need to get there the day the [weekly] sales start, she says, usually Sunday. Stores run out quickly and they may not restock.

Savings also hinge on loyalty to a particular store and a small initial outlay, says Briana Carter, the founder of BargainBriana.com, a coupon site that also offers a map of local deal bloggers, to help shoppers find promotions that vary by region. CVS prints its Extra Care loyalty bucks along with your receipt, so someone buying Crest Pro-Health toothpaste ($3.50 before a 75-cent manufacturer s coupon and $3.50 store rewards) would pay $2.75 and walk away with $3.50 for their next purchase.

It s easy to get drawn in by the something-for-nothing lure, but remember to limit your stocking up to what you actually need. I currently have a cabinet full of free toothpaste, deodorant and body wash -- enough to last me well into 2012. In a tiny New York apartment, those freebies are taking up valuable real estate.

Yet finding zero-sum combos without number-crunching every circular sale can be relatively easy. Deal sites including Fat Wallet, SalesCircular.com and Coupon Cravings post regularly about the best deals at big chains, even pointing out where you can get the necessary manufacturer s coupons.

It s definitely worth the effort, says Carter. I hardly ever pay out of pocket for toothpaste. Toothpaste is the chief free item; other common product categories include shampoo, deodorant and other toiletries.

We re featuring valuable coupons and sales each Friday to help you spend less on the items you buy. Found a deal we missed -- or looking for a better price on a specific item? Email me at kgrant@smartmoney.com or send me a tweet @kellibgrant.

1) ShopBop.com

The site s February sale offers 30% to 70% off select designer apparel. The catch: Even a 70% discount leaves many post-markdown prices at several hundred dollars. (A $1,295 Rachel Roy dress, for example, is currently $388.50). Returns aren t accepted on final sale items, either. Shop carefully.

2) iTunes gift cards

Through Feb. 20, BestBuy.com is offering free shipping and a 10% discount on iTunes gift cards. On a card worth $25 and priced at $22.50, that s the equivalent of two trendy songs (i.e. $1.29 on Apple s 69 cents to $1.29 scale) free.

3) Gap

Save 25% on new items in stores through Feb. 21. Online, get the deal with code GAPNEW25 at checkout. Jeans are excluded.

4) FTD.com

FTD.com is currently offering 15% off most bouquets on the site. Save an extra 20% (through Feb. 28) by entering COUPONCABIN20 at checkout.