On: 'Extreme poverty' to fall below 10% of world population for first time

[crdb]

To help you answer that literally: according to Simon Mann who did it successfully twice and failed once [1], a successful mercenary invasion and peace-keeping effort in a country like Sierra Leone cost around 1 million GBP in the mid-1990s.

[1] http://www.amazon.com/Cry-Havoc-Simon-Mann/dp/1743142307