It really isn't as amazing as it sounds. To do it at BestBuy I had to purchase the SBC-Yahoo starter pack for $95 after taxes. There is a $75 rebate and a $15 rebate for it. So if you get all of your rebates, you save $13 (SBC shipping-and-handling fee for the kit they would otherwise mail to you) minus the $6 for taxes and the postage stamp, saving you $7. The big savings is that you get the $75 Best Buy gift card, which you also have to mail away for and hope you receive, like a rebate.
If it all comes together then you hit a home run on the deal, getting the DSL for less than $10/month.
Thing is, you have to gamble that $90 + tax to go buy the starter kit at Best Buy. Reward for the gamble is the $75 gift card. So when you look at it that way, it isn't as hot as it might seem.
Now...what the heck am I gonna do with that $75 card. If I spend it at Best Buy it's like a $40 card since just about everything there is severely overpriced. Their video card selection and prices were laughable. Probably have to use it for a hard drive deal with more rebates of course.