The secret of the e-commerce experience
It's genius, I don't know why I didn't think of it before - set up an online shop, let people pick out their goods and then once they've handed out their credit card details and confirmed their order, proudly announce that some of the goods they've ordered are out of stock but process the order for everything else anyway.
Unfortunately the following item(s) are now out of stock. This amount has not been charged to your card. We are sorry for any inconvenience this may cause. Please try again in a few days, as we should receive more stock shortly.
And then, the really smart bit is this - make sure the only way that your customer can cancel or amend the order is by making them call a national rate 0870 number! See, I told you it's genius.
Anyway, I could do all this, but alas, what's the point when Argos do such a fine job of it already.