Reported costs for active bases like Colombia and Yemen are implausibly low.

Evidence

The OCS also reports costs of less than 5 million apiece for Colombia, Yemen, Thailand, and Uganda. Given current levels of military activity in each country, this seems highly unlikely. The costs of the military presence in Colombia alone could easily reach into the tens of millions a year, in the context of more than 9 billion in Plan Colombia funding since 2000. — David Vine, Base Nation_ How U.S. Military Bases…, 609