Are you a student? I remember paying about 7 pounds for Edinburgh castle and I believe that would be about the average for each of the cities. Cities usually offer a tourist discout card. Look into that and see if it is worth the purchase. Sometime, you spend the money on those cards thinking you'll save money, but in the end, you don't get your return on it. I would stick with the pubs for lunch. As for food, stick with pub food. Pub food is realtively cheap and is pretty filling (and no I'm not merely talking about the beer.)