It depends on how many players you have as its P2P, however if i remember correctly a 3v3 (aka 5 players) resulting in a standard rate of about 15kbps, so lets say 3kbps per player.

So for 100mb you're looking at 55hrs non-stop 3v3 gaming.

I would also check the bandwidth of your phone - you need a good upload speed to play without lagging...

I asked what the bandwidth requirements were for playing (slightly off topic, I know), the answer I got was:

1 vs. 1 ~24 kbps

2 vs. 2 ~64 kbps

3 vs. 3 ~105 kbps

4 vs. 4 ~145 kbps

5 vs. 5 ~186 kbps

{thanks to Spooky}