Android - Data Roaming

[Hemps]

I have a spare Samsung GIO that I placed an MTN 3G sim I get for work inside it. (used to be in a dongle)
My iPad is tethered to the phone.
So far I have used +-350mb since January connecting to work when out of the office or after hours.

I see in the settings on the phone that "data roaming" was checked and has been running since January.
APN's MTN Data
I have not been out of the country or anything, does this effect me?
will I receive some huge bill?

[cpu.]

I'm with 8ta and if roaming is off, internet is off. It's for networks like Cellc and 8ta that roam (when no signal received from their own towers) on Vodacom and MTN.
I don't know if MTN roam on any networks, but think not.

[Ol' Mean Bastid]

if you haven't been out of the country it shouldn't be a concern