Sometime in 2015 the lenovo k3 note(aka k50) was released costing about $150 (36,000 naira at that time). To the pro geeks this was the one device that offered so much at that rate. 2GB RAM, 64bits processor, 4G etc.
Fast forward in 2017 we have the exciting Xiaomi 4x and note 4x series. Costing around $150 and slightly less, the 4x comes in many variations that features a snapdragon processor, 2GB/3GB/4GB RAM, 16GB/32GB/64GB ROM, fingerprint sensor and latest Android os via OTA.
Which ever variant of the 4x you pick for an upgrade for your current phone will deliver so much for the best price.
Just like the Lenovo k3, the Xiaomi 4x isn't easily available on local stores, but one can order one from popular Chinese e-commerce site AliExpress or from the international section of local e-commerce site Jumia. Many nairalanders are already using the 4x and can give testimony. Many used the k3 note from 2015 too.
If you are still looking for an affordable phone that gives you the best deal for your money, you might want to take a look at the Xiaomi 4x series.