MTN just released new code for their customers to enjoy their services.
1: 250MB for valid for 3 day's; costs 100
2: 1GB valid for 7 day's; costs 200
3: 4GB valid for 30 day's; costs 1000
It's real and available to all the MTN users.
Simply Dial *131*65# and select anyone from the options you will see below.