It should come as no surprise to those of us that shop via the Internet that shipping costs often undermine the bargain. Some companies so inflate shipping costs that even $4 a gallon gas doesn't make their wares a wise purchase.
One site that will come in useful in fighting the shipping cost blues is Freeshipping.org. This site aggregates free shipping deals from over 700 stores, including biggies like Amazon, New Egg, Target, and Finish Line.
I'd suggest using this site when deciding from whom to buy an item that is sold by many vendors. For example, an Apple iPod Nano, 4 gig 3rd generation, is selling for $144 on New Egg, $145.95 on Amazon. New Egg, however, wants $5.99 for three business day shipping, while Amazon offers free supersaver savings (usually a bit slower, but not always.)
Another similar site, Freeshipppingon.com, is also worth checking out.