The consumer tariff will be £25 a month for up to 20 megabytes of data. Every megabyte over that will cost £1. So mmO2 calculates that a typical consumer who sends 100 emails (including 10 with pictures or sound clips), plays 4Mb worth of online games, surfs 100 pages on the net and downloads four music tracks and three video clips will spend £44 a month, or £1.40 a day.