Hey samoht04
Right, second time i'm trying to post this, work browser crashed on me.... grrr...
So, go into the EA sims store (after logging in) and make sure you change the language to English (UK) - it automatically defaults to English (US). To change the language click on the small globe on the bottom left of the page - took me ages to find it the first time.
Then you can see how much each points pack costs in £. So 1000 points = £7 = 0.7p per point (hope I got my maths right). And you also get your free item. I normally pay by pay pal but you can use cards as well.
Alternatively you can buy a Sims Cash Card with preloaded points. I know Amazon were selling them. Gamestation also sells them, and they're on offer right now. For a 1000 points you pay £5.99 with free UK delivery (just checked for you). Or you could buy them in the shop. Might be easier for you to do that as you can then pay cash over the counter. Game, HMV, and PCWorld also sell them, no idea if they've got an offer on them though.
Just let me know if you have any more questions or any problems.