HI, I would agree with Maggy J do your homework,the three angry birds issue came up with the free app only, if you downloaded it they got their "money" by getting it to send data to your phone in the form of ads! the paid for version did not do this.
I am with three and they do some very good bundle deals with very high data useage,and i have never gone anywhere near my official limit if that is what you are worried about.
As always with smartphones you have to be careful what you download if in doubt do not download,as some apps are data as well as battery heavy.
The thing i always do is my research on the net then go see when your armed with some info and can ask questions.
