Firstly, it's worth explaining what each unit of measurement is worth. One megabyte (MB) is made up of 1,024 kilobytes (KB). The next measurement up is a gigabyte (GB), which is made up of 1024MB. The most popular plans offered by mobile phone companies are 1GB, 2GB or 5GB of mobile data allowance. But deals can start as low as 100MB depending on your needs. And for those data hungry phone users, you can even get an unlimited data plan. Though this will bump up the cost of your monthly mobile phone deal.