Does it matter if I purchase from the states. I know £12 translates to roughly to $19 USD. I've never purchased anything with a different currency. Just wondering if there is any 'foreign' charge or anything like that.

Any additional charge will depend on your payment method/credit card provider.

Most do no additional charge anymore these days.. They just use a crappy conversion rate and make huge profits, PayPal for example is a star with it. What can you do about it, not much.

But is this 2, 3 dollar difference so important for you?

It might be worth just going straight to S2.

edit: off subject, good lord I've never heard of Nigella Lawson before. Hubba hubba
edit2: I figured it out

I agree that S1 is pretty pointless, you may as well just get S2.
The cost is the same if you buy it straight off or get S1 then upgrade.

Here's some quality Nigella for you - http://www.youtube.com/watch?v=RtS2Ikk7A9I