A lot of times, shopping online makes more sense than shopping in a store. Web sites are open 24 hours a day and often have more selections and different discounts than stores have. Also, it's easy to get a discount at an online merchant - you don't have to have a physical coupon, just a code made up of letters and/or numbers that you enter while checking out.
If you don't already have a coupon code when you're at the online check out, do a search for coupon codes to see if you can get a better bargain. For example, if I was doing my online shopping at Aeropostale, I would search Google for "Aeropostale" "coupon code." I would probably get a ton of sites that are made up purely of coupon codes, but a lot would give me the same code. I'd check out the first six or so and see if there were any discounts applicable to my purchase, and use the best one while checking out.
On a side note, one site to keep in mind is igive.com. When you sign up at this site and make a purchase at one of the participating online merchants, a percentage of the amount of your purchase is donated to the charity of your choice without any extra cost to you. It's really a great way to give to charity without breaking the bank!
Happy online shopping!