Your favorite shopping buddy? Your app.

Once your most trusted shopping companion was your best friend. Now it’s your smart- phone.

Thanks to new mobile applications — including ShopSavvy, RedLaser, TheFind and Amazon Mobile — you can scan product bar codes to learn an item’s best online or offline price. “This creates a Wild, Wild West shopping atmosphere where consumers gain control,” says Chuck Palmer, principal marketing strategist at ConsumerX Retail.

The win-win for shoppers and chains? “If you’re confident,” Palmer says, “you’re more likely to spend.”

The pros:

Stores are motivated to match competitors’ prices or services.

Sales clerks may sweeten deals with perks or extended warranties.

FourSquare.com, Gowalla.com or AT&T ShopAlerts tailor pop-up specials — even on games — if you check in, Palmer says.

The cons:

Stores may divert your search to their own apps.

Some brands give big chains individualized bar codes, so you must compare features.