There are some countries where people cannot easily create paypal accounts. Is there another way to transfer money online?
Western Union is available in most African countries. For example in South Africa, Absa Bank's offer western union services. You can setup most popular shopping carts to allow check out, and display instructions on sending payment with Western Union.
It's even available in Nigeria http://www.westernunion.ng/ a country I don't think PayPal is available as of today.
Bitcoins seem perfect for this. I'm not sure how big it is in Africa at the moment, but apperantly it's becoming bigger in countries like Kenya (http://theconversation.com/bitcoin-fuels-africas-banking-revolution-16044). The cost to transfer bitcoins is very low, you only pay a fee when you buy/sell them for fiat currency.
You can just use a service like Coinbase to automatically get dollars for your BTC. This way you won't have to worry about fluctuating exchange rates.