Go through your results for flights to Kigali in Rwanda with Netflights. Although Ethiopian Airlines usually has the best prices, it's best to double check what's available for your travel dates.
If these flights are too expensive, try searching for a different time of year. So if your dates are flexible, consider looking at different times of year.
But if you're struggling to find flights to Kigali that work for you, try looking at other airports in Rwanda.
For even more options, check what other airports you could fly to Kigali from. You might be able to make a saving by going from a different airport or city.