Whether fashions, electronics, hiking equipment or pet supplies is your retail drug of choice, listen up. There is something you should have with you every time you head out of the house for a little retail therapy, and it’s not your limitless AmEx.

No, you need your smart phone.

You are not packing your Droid or your iPhone or your BlackBerry to chat with your friends while weaving between racks (please don’t do that), but to find the best deals possible on just about every item on the mainstream market.

There are a slew of low- and no-cost apps for your smart phone.

Some are operating-system-specific (i.e., they work only on your Droid, your iPhone, etc.), but all can leave you with enough money left over to enjoy another kind of app — an appetizer — and more with your post-shopping dinner.

All of the apps are available at the "app store" on your phone or the manufacturer’s website.

Check them out.

COUPONSHERPA
This app helps you find the best online coupons by acting as an aggregator for discounts at stores such as J.C. Penney, Quiznos, Gap, Finish Line and thousands of others.
Available for: iPhone, iPod Touch or iPad
Cost: Free

GOOGLE SHOPPER
This app allows you to stand in a store and find out whether the product you want is available elsewhere — in a store or online — for less. Sure, we’ve talked about shopping apps like this in the past, but this one is a bit different because it not only allows you to search by scanning the item’s bar code, but you can also use your voice.
Available for: Android
Cost: Free

SHOPKICK
This app is like FourSquare/a scavenger hunt. Numerous high-profile technology blogs and online tech magazines have called it one to watch in 2011. Scan items and earn points that can be redeemed for prizes, gift certificates or charitable donations.
Available for: Android and iPhone
Cost: Free

SHOPSAVVY
Compare prices from 20,000 retailers by scanning the item’s bar code with the camera feature on your phone. Need a little reassurance about your buying decision? The app also provides reviews.
Available for: iPhone and Android
Cost: Free

REDLASER
This operates the way a lot of websites do by finding the best price on a particular item — but this one will do it while you are standing in the store. Just scan the bar code, and the RedLaser app will look up the product and give you a price comparison across the Web.
Available for: iPhone and Android
Cost: Free