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.<p>[1] <a href="http:&#x2F;&#x2F;www.amazon.com&#x2F;Cry-Havoc-Simon-Mann&#x2F;dp&#x2F;1743142307" rel="nofollow">http:&#x2F;&#x2F;www.amazon.com&#x2F;Cry-Havoc-Simon-Mann&#x2F;dp&#x2F;1743142307</a>