Finding information about visas in West Africa can be a bit challenging especially when requirements are different for those living in other countries, travelers with direct/indirect flights, etc.
After checking government and travel websites with contradictory information, we learned and decided that it would be better and cheaper to buy our Burkina Faso visas at the border crossing between Mali-Burkina. It should have been around $40US.
While in Mali, we learned from our Italian CouchSurfing host that a "new requirement" upped the price of the Burkina Faso visa to ~$120US. Upper further inquiry, a Returned PCV stated that another recent upgrade made the visa cost ~$185US!
Sigh...at the border crossing, we stayed quiet and kind to see what would happen. The immigration officers actually spent much time flipping through our passport pages as we already built a collection of stamps (gotta love those passport stamps as a traveler!).
"For the three visas, that will be 196,000CFA," the officer stated without hesitation. So, that would be 65,333CFA (~$134.70US) for each of us. Interesting!
We were happy enough not to pay the $185US, so after the bus full of Africans waited for us to finish, off we all went! Finally arriving in Bobo-Dioulasso eight hours later, we were exhausted!