Recently I saw a post about the Nigerian exchanges and i realized that the buying rate is 20-30% higher.
That means that the people in Nigeria buy at +30%, BUT that also means that the Nigerian exchanges buy at +25%.
Buy rate at BitFinex at 05:00 GMT = $918
Sell rate at Naira Exchange at 05:00 GMT = $1147
That is a huge difference and it can surely be used for arbitrage.