$2.20 on some websites and no shipping cost
The Auzentech X-Fi Prelude will be better in games than the all ASUS cards, but it will also cost nearly twice as much.
Yes -- sound cards are available for a wide range of prices from about 10$ to over 1000$
It depends on what kind of cards they are.
Yes -- most modern sound cards consume much less power than before.
The cheapest sound cards start around 30-40 USD. Of course there are really pricey cards aswell, for example the RME HDSP 9632 Hammerfall. In general the a sound card cost between 30-450 USD
£1.00
$10
It depends where you buy it from.
You can buy Firewire sound cards, but they do cost a bit more these days.
Oh, dude, let me grab my calculator... just kidding, who needs that? So, if 9 cards cost 25p, that means each card costs about 2.78p (25 divided by 9). Now, if you want 36 cards, just multiply 2.78p by 36 and you get around 100p. So, 36 cards would cost approximately 1 pound. Easy peasy, lemon squeezy!
It is around £20 ($30)
$10.00 mate... they are AWESOME!