I follow www.moneysavingmom.com on a regular basis. She always has wonderful things to say and great deals to get!
Recently I was reading on her blog about purchasing online. She has lots of links to sights where you can get coupon codes as well as where you can purchase and get $ back.
I researched this when I bought my laptop a few weeks ago. You do want to do your research before you purchase. I found out by going into Office Max that I actually saved about $160 by buying in the store vs. online. But just yesterday I researched for my mom on purchasing the Sketchers Shape Ups and she will actually save about $18 by ordering online. And shipping is free so they get delivered right to her door!
Below is the link to MoneySavingMoms blog about purchasing online.