The data back her up. The World Bank publishes rough estimates of price levels in different countries, showing how far a dollar would stretch if converted into local currency. On this measure, Kenya is more expensive than Poland.
The cost of living is generally higher in richer places, a phenomenon best explained by the economists Bela Balassa and Paul Samuelson. They distinguished between goods that can be traded internationally and many services, like hairdressing, that cannot. In rich countries, manufacturing is highly productive, allowing firms to pay high wages and still charge internationally competitive prices. Those high wages also drive up pay in services, which must compete for workers. Since productivity is low in services, high pay translates into high prices, pushing up the overall cost of living.
Among developing economies, however, the relationship between prices and prosperity is less clear-cut. Prices in Chad, for instance, are comparable to those in Malaysia, where incomes are 14 times higher. Fadi Hassan of Trinity College Dublin finds that in the poorest fifth of countries, most of them in Africa, the relationship goes into reverse: penniless places cost more than slightly richer ones. A paper in 2015 from the Centre for Global Development (CGD), an American think-tank, accounts for various factors which could explain differences in prices, including state subsidies, geography and the effects of foreign aid. Even then, African countries are puzzlingly expensive.
The relative cost of food, compared with other goods, is higher in poor countries. In Africa, the absolute cost is sometimes high, too. Nigerians would save 30% of their income if they bought their food at Indian prices, finds a recent study by the OECD, a think-tank. Meat costs more in Ghana than in America.