Basically, you cannot really determine how much data you would consume within a month it is still depend on how you use it. Mine I am currently still using my previous plan which SuperSurf. The only difference of the legacy plan from GoSurf is that with the GoSurf your data connection will not slow down though you are only allocated consumable data per month. If you exceed the allocated data you will be charge 2 php/mb. With the old plan, you have an allocated 1GB/day or 3GB/month which ever comes first. Once you reach the allocated data your data connection will slow down, but the good thing even though your data speed is slow you can still continue to use your data but no recurring charges even you exceed the data allocation. For more information on GoSurf you can refer to this link GoSURF | Plans and Promos | Mobile Internet - Glob.