Don't agencies have some kind of de minimis threshold for just running out to the store and buying basic stuff? I thought that's why the DOGE freeze of government credit cards a few months ago was causing labs to cancel experiments and employees paying out of pocket to feed horses and working dogs.
So the military does have a strict procurement process for rocket fuel, but they generally refuel their civilian vehicles (vans and such) with a government credit card at normal gas stations.
At least that's how I understand it.