[taligent]

The small value transaction is called a pre-auth and yes it is designed to test whether the card works. It's not a big deal in most countries since it just disappears automatically. But IIRC in the UK it doesn't. Google probably figures they can use the same rules in every country. Pretty dumb move.

The reason stores do it this way is because of legal reasons. They can't bill your credit card until it is shipped but yet need to know you have the money before building it.

[pja]

They're still issuing a pre-auth for the whole amount even after the small-value one, so what's the point? They could just pre-auth the full value in the first place!

They can't legally take payment until they actually ship regardless so they're going to have to put the transaction through the card at a later date whatever they do initially.