Luanda is the most expensive city to live in the African region, and world-wide. The extremely costly safe expatriate accommodation, imported produce and costly international private schooling are among the main factors that have kept Launda at the top of the rankings in Africa.

Overall African countries are some of the poorest and least developed in the world, with relatively low local cost of living expenses; however the cost of importing and transporting the international standard of goods that expatriates expect to purchase in the cities in this region makes it extremely expensive to maintain the lifestyle that they are used to.

Kinshasa in the Democratic Republic of the Congo (DRC) is the second most expensive city in Africa (and 10th most expensive in the world).
http://www.xpatulator.com/cost-of-living-article/Africa-Expat-Cost-of-Living-Comparison_711.cfm