Have atleast N25 to N50. Place n dont end your call until ur credit runs out n mtn machine start tellin u dat ur credit is low etc, but hold your call b4 it disconnects. NB: dt d hold may go on 4like 5mins or more n it wil disconects itself n ur credit wil com back. Gudluck! Also, note dt,it may nt work in al areaz.