I think Fry's has good deals on those sorts of things, if there's one around you.
When I need these things that are hideously overpriced at big box stores, I actually go to Tiger Direct. Now, it's a terrible, terrible [terrible] place to shop, but they've got decent prices on things like fans or SATA cables that New Egg charges $5 shipping for. Anyway, I think there's only 3 of them, so that probably doesn't help you too much.