In terms of cost this was a cheap meal for us, I say "for us" because we have been cooking a lot of Jamie Oliver meals so our cupboard contains a lot of the ingredients he frequently uses. This sticks with the policy of the book but if you were starting out with this type of food then forking out for the base ingredients will feel expensive. Saying that, however, it will let you then cook a lot of the recipes from the book cheaply after the initial cost.
I also made a pudding tonight from the book. 300g of frozen pineapple, 300g of natural yoghurt and half a teaspoon of honey mixed in a blender. It made an amazing creamy icecream/frozen yoghurt. I think I will be trying this with lots of different fruit in the future - next up frozen berries or banana!