Your mobile phone with MTN line
The screen shown in the picture above shows up
Type 1 and send to get 500MB data free on MTN line or
Type 2  and send to get 1GB data for free on your MTN line
NOTE:
The free data is valid for 7days.
This is just a free offer from MTN and therefore does not require any software..

Read more from http://nairaclass.com/forum/index.php?topic=879.msg897;topicseen#msg897