I think most customers still get VERY attracted to the FREE shipping promos offered by sellers. The word FREE alone does the trick may it be for shipping or for another product.
Some sellers actually incorporate shipping costs to their products and then claim free shipping but its not actually free. If as a customer you don't bother doing the math then you'd think you landed a great deal. I think it's human instinct to go where there is a freebie offered.

I mean I would too!
"In a recent comScore study, 72% of consumers said that if an e-commerce site eliminated free shipping, they would use another e-commerce site that did offer free shipping. Last week the LA Times reported that this year, nearly 80% of consumers said they were more likely to shop online with a retailer that offers free shipping, compared with 60% who said that last year." - an excerpt from an article called - Is free shipping a must in this economy? Some of the comments posted by readers are quite interesting and a few have really tips as well. To read more please visit this link:
http://www.grokdotcom.com/2008/11/12/is ... s-economy/Cheers!