When the weather is bad and the crowds are frightful, it’s time to head indoors, sit down at your computer and do a little online shopping.

What surprises many new online shoppers is how much money can be saved by shopping from your own living room. Used judiciously, online shopping codes can save you a lot of money and time. What’s best is finding boxes at your doorstep days later. No schlepping to the mall, dealing with parking and other people, and then lugging things home.

But to get the most bang for your online shopping buck, you need to understand the fine art of coupon codes and their various uses. If you just go shopping online, ignoring the various promotional deals, you might spend more than you would in a brick and mortar store, and who wants that?

Here’s how to get the codes.

First, for each online store you visit, sign up for their newsletter or to be on their mailing list. Sure, this means more email, but if it’s a store you like, it’s worth the bigger mail download. Trust us. Stores routinely send notices of “secret” sales, unique coupon codes good for 10 to 50% off your purchase, and promos offering free gifts with purchase and free shipping.

Second, when you receive a package from an online store, be sure to check all the paperwork. Often, the online stores tuck coupon codes into the box enclosures for you to use later.

Third, check out the various coupon websites designed to help you find and use online coupon codes. If you Google “online coupon codes” you’ll be met with a wide array of choices in websites. Try to find a good site with a message board; you can find more deals at the message board or find reviews of various stores and experiences from people using certain coupon codes.

Finally, pay attention to all that paper you usually don’t pay much attention to. For example, your cable TV or satellite TV bill might have a coupon code for Home Shopping Network. Your Visa bill might come with an enclosure offering special deals and discounts at various stores if you use your Visa card.

Then, learn how to use the codes.

Once you have some coupon codes you might want to use, how to do you use them? Usually, you’ll enter a code at checkout. Each retailer has a different set-up. Some will ask for a code before you hit the “checkout” button, while others ask for it last, just before giving you a final summary before you submit your order. Be sure to look carefully for the box to enter the code. The site might ask for a code, a promo code, a discount code, or a special offer code. Whatever they call it, that’s where you enter your code.

Once you enter the code, look for proof that the site has accepted the code and applied any discount. For example, if the coupon is for 10% off, make sure that 10% has indeed been deducted for your total. Again, depending on the site, this will look different. For example, some sites might take the discount off each individual item, and the discount noted on each line of the order. Others might take the discount off the total purchase price and that will be noted at the bottom of the order.

If the code is not accepted for some reason, be sure to read the code details again. Has the coupon code expired? Did you purchase enough? (Some free shopping codes require a minimum purchase, for example.) Are all the items on the order eligible for the discount? Did you enter the code correctly?

How much can you save?

How much you can save using coupon and promotional codes depends on where you shop and what you buy. If you have a lot of shopping to do, you can literally save hundreds of dollars. If a toy store has free shipping on a $75 purchase, you might save $10 just on the shipping alone.

You can save even more by hunting for deals to combine. You can’t usually “stack” coupons, which means to use more than one coupon at the same store at the same time. However, you can often “stack” a free shipping code with a dollars-off one. For example, that same toy store with free shipping on a $75 purchase might allow you to also use a code for $10 off the $75 purchase. So now your savings has increased from $10 to $20 just by spending a few extra minutes finding another coupon code.

How else can you save?

There are a myriad of ways to save when shopping online besides just using coupon and promotional codes. Combine these deals with coupons and you really have a great deal.

For example, look for “buy one get one” promotional deals. It might in the form of a free gift (free tote with purchase) or a free like item when a similar item is purchased. Combine these deals (which usually do not require a code) with a coupon and free shipping and you might reduce your order total to half of what it might have been without codes and special promos.

Be sure to also check out the online sites that give you cash back or points for purchases. Simply link through their site (entering the store via a link on the site’s page) and then go shopping as normal. Use all the special promos and coupons you would otherwise use, but you’ll also get a cash back rebate or points you can redeem later for gift certificates.