Infographic: What can you do with 30GB of data? AuthorJessica Clarke. Posted01/07/16. Share. So you’ve just signed up to iD prepay and are about to avail of our generous data allowance of 30GB per month as part of your plan. But what exactly can you do with 30GB of data? Sign up to iD prepay now and avail of 30GB of 4G data, 300 minutes to other networks and free calls and texts to your mates on iD. All for a bargain-busting €15 a month top up.