I would like to suggest that you allow users to individually customise their goody bags. For example as a 'light' user I only really use one of the three elements to my goody bag, and rarely use even a quarter of the others. For example your cheapest goody bag of £5 allows users 100Mb data, 120mins of calls, and 500 texts. Why not allow users to partly sacrafice one or more of these elements in favour to another? e.g. on the £5 goody bag, sacrafice 60 mins, 250 texts say, but gain an extra 100-150Mb of data?