You can just mushup on MTN with only 10 Gps and get 60 minutes of airtime by just doing this
1. You have to activate free
after one by dialling *550# and choose option 6 and follow the procedure after you have activate your free after one come back .
2.Dial *567# and choose mushup for self or others , choose option 1 send and choose option 2 then you will see (0.07- 4.99) dial 0.1 and send choose option 1 send and again option 1 now you're done with your mushup.
Come back and call any MTN number of your choice and talk for one hour.