Eve online: the best game I'll never play.
I find all the politics and dynamics of Eve Online super fascinating. There's maps, propaganda, hierarchies, dictators, bribery and even actual spies on each alliance, it's insane.
AFAIK there's an in-game currency that can be bought with USD or earned. The biggest ships (Titans) can be worth thousands of dollars. The last big war was two years ago, in which ended up costing well over $300k.