MTN offers free 1000mb.

MTN FREE 1000MB(Nigeria)

Steps
(1) Simply Send MYAPP to 131 and earn 100MB instantly

(2) Send STOP MYAPP to 131 again to unsubscribe

(3) Then Send "MYAPP" again to 131 for another 100MB

Keep Repeating step 1 & 2 till you get 1000MB

You check your MB, dial *559*4#.