Information About Reltel Fixed Wireless- Price

I am interested in getting a reltel fixed wireless phone  which will be used in portharcourt just for making and receiving calls .I will be happy if any one can answer these questions for me .How much does it cost to get a line and activate it?, How much is the least amount to charge the phone/buy credit? If i charge it with the least amount how long will it last before i am required to recharge it again if i only receive calls ie the duration a card can last if there is still credit on the phone before it expires.