To add to what davycro said, entry level Android devices are becoming price competitive with feature phones. Phones are seen as a long term investment, so poorer families often make sacrifices to acquire them. It wouldn't be unheard of for one to spend up to half their monthly income on the purchase.

Mobile data costs KSH. 8/MB, about 10 US cents at its most expensive. This is still out of reach for a sizeable portion of the working population, but the situation is rapidly improving.

I think most people in cape town will spend up to $100 for a phone. It's by far the most important possession here. Data plans are prepaid.