I remember when I was there a decent meal for 2 was still 25 pounds, that (at that time was about 46 dollars). The place is awesome but jesus is it expensive. Clothing there is pretty cheap though, I got a few shirts for 3 pounds each. Oh and I couldn't resist getting some BK's (ahh yes brittish knights son) for like 15 pounds or something rediculous, probably because they're more dorky there than here
Hit up the science museum.... it's pretty off the hook.
Another thing there (and most brittish colonies I think) is you pay for rent and whatnot weekly, I'm bad enough remembering to pay once a month.