Not sure if this is a bug or a feature.

I had approximately $270,000 expenses in the Alliance/GDI category when I had 0 allies and have the free GDI bonus. I had declared war on a suicider and forgot to declare peace after he was dead. After declaring peace the expense went back to $0.

The expense was equal to the land expense. In other words, my land expense was $270,000 and my Alliance/GDI expense was the same.

So to summarize:
1. 0 allies
2. Free GDI bonus
3. Declared war on someone
4. Alliance/GDI expenses = Land expenses
Expected behavior: Alliance/GDI expenses should be $0 in this case, since there are no allies and GDI is free.

deccing war causes expenses and has caused since ........

Declare war costs $10 per acre per turn in upkeep, and is added to your Alliance/GDI expenses.

Hmmm, I had forgotten about this one. I usually have guys declare war on me on the tourney server and then I continue farming them. I always by reflex almost declare peace/run as little turns as possible when I declare. Now I remember why I do that, lol.

10$ an acre

Ah, now i see that in the "Help on Attack Information", heh, learn something new about this game all the time.