Data usage while using apps?

[greatwool531]

I have recently bought an android phone and have downloaded a nub err of apps.

I have a 750mega-bite time limit per month and as this is my first month i am not sure how long this will last. because of this i am trying to save as much data as possible in the first few months

i have apps that have music videos on them and was wondering if with each video used i lose data from my contract.

also much data is 750mega bites? how long will this last me? i mainly only use my internet for facebook,gps and music videos

thanks