No matter what, it's always expensive to fly into/out of Niamey from outside of Africa (and from inside of Africa usually too). One of my best friends is actually on a plane from PHL
as I type this on her way to live in Niger for 3 years or so, and the price was incredible! And that was with an advanced purchase.
All that being said, my guess (incorrect or not) is that AF
will be the most expensive. I would say go through Tripoli as ENU mentions, then hook up with EK
. Also, will you not need a visa to get into Niger? And factor any transit visa possibilities into the final cost as well!