Mtn is giving out some freebies to there customers, some customers gain 500mb or 1gig depending on your sim.
To activate it, you just have to dial *449*2# to activate your offer and after dialing the code, you will get a message like this.. "Congratulations! You have successfully activated FREE 1GB valid for 7 days. Please dial *559*4# to check balance."
HOW TO GET MTN FREE 1GB OR 500MB DATA
==> For 1GB dial *449*2#
==> For 500mb dial *449*1#
I hope this helps