As retailers increase their selection and service online, there is less and less reason to step into a store these days. But what seems like a great deal initially can quickly come to a screeching halt once you add the costs of shipping. Plenty of free tools are at your disposal to make sure you get the best deal. Here are seven tips on how to avoid spending unnecessarily on shipping costs for your online purchases. (For related reading, check out Shopping Online: Convenience, Bargains And A Few Scams.)

1. Find The Secret Code

Just because a site you are shopping isn't advertising the offer to you, don't assume it doesn't exist. Several dedicated websites now allow shoppers to locate deals from any retailer in just seconds. A quick Google search can tell you whether the site you are about to buy from has a better offer out there. Type the name of the retailer you are shopping in combination with a search time like "discounts" or "free shipping offers". In many cases, you can find valid discount codes to enter upon checkout and save on shipping altogether. (For more, see 4 Coupon Sites Worth Checking Out.)

2. Buy When Shipping Is Free

Perhaps the easiest way to avoid getting caught up in a shipping mishap is to commit to buying only at sites that never charge for it. Sites like Zappos.com have committed to never charging shipping fees on purchases or returns. To find others, visit Freeshipping.org, a site committed to promoting only online retailers that offer free shipping. To date, the site lists close to 4,000 retailers.

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3. Shop On Dec. 17, 2010

This is the one day of the year when you'll never have to worry about paying for shipping - at least from an estimated 1,000-plus merchants who should participate. Even better, in-stock purchases you make on this day are guaranteed to arrive by Christmas Eve. For more information, visit freeshippingday.com.

4. Shop Around

Some things really are too good to be true, and unfortunately, sites that offer free shipping can sometimes fall into that category. It is not uncommon for retailers to tout free shipping benefits, but then charge a higher price per item to cover their expenses as a result of the shipping policy. Like a discount code search, a few seconds on Google can save you cash. Simply type in the product name of the item you are considering and use an online product comparison tool like Google Product Search, NexTag.com or BizRate.com. The results will sort all the online retailers who offer the product, and at what price, so you can determine whether that free shipping deal really is saving you money. (For more tips, see 12 Ways To Shop Smarter.)

5. Cut Out The Middleman

A new ecommerce trend quickly picking up speed is the option to purchase an item online - and pick it up at the retailer's brick and mortar location. The benefit is you know the store has your item in stock (because you already purchased it online), and you'll get it even faster than waiting for it to be shipped. The pick-up waiting period varies, but some retailers can transfer the merchandise in a matter of hours. While this trend is still catching on, you can take advantage of it at retailers like Nordstrom, Sears, Best Buy and Wal-Mart.

6. Become A Fan

Free shipping and social media often come hand in hand. As tools like Facebook and Twitter are becoming part of our everyday lives, retailers know that word spreads like wildfire, and keeping their loyal customers happy is a must. As a result, many retailers now reward those who become a Facebook "fan" or Twitter follower with exclusive promotions and free shipping deals. (To learn more, read Social Buying: A New Way To Save.)

7. Time Is Money

Particularly when you're purchasing for a special event or holiday gift, allowing plenty of time to receive your purchase can lead to big shipping savings. Many retailers who offer free shipping do so only on their standard service. While delivery times vary by retailer and carrier, experts suggest that you allow at least 21 days for the arrival of your purchase. Most retailers do not take anywhere near that long to ship your purchase, but they state it to ensure that they can "under promise and over deliver". By ensuring that you can wait up to three weeks to receive your goods, there's no need to upgrade to more expensive shipping.

The Bottom Line

Shopping online offers plenty of benefits like increased selection and often better prices. By taking a few minutes to make sure you are getting the best offer, you'll never pay shipping, or higher prices than necessary, again.