There are many costs of wars; salaries, material costs if more than what the soldier himself brought to battle, munitions, same same.
Other costs include:
lost wages from normal activities, loss of companionship, lost production of civilian activity, and loss of emotional contribution of member of family and close-in society.
Over the history of the earth, we can assume some averages. WE have had skirmishes, battles and wars, each larger than the other, for different durations of time, with different objectives for the initiating party.
If we count ONLY 12 skirmishes, 5 battles and 2 wars, per year, from 3,000 bc till the present time, we must guess on the size of the warring factions. Let's give each side 100 for a skirmish, 1,000 for a battle and 100,000 for a war.
IF we use 1956 as a baseline for costs, [when the US dollar was worth a dollar], we can give an arbitrary value to the increased costs of goods world wide, although an economist can be more accurate.
WE are counting from year 3,000 b.c. to 2007, or 5,007 years of wars. Who was it that suggested we love our fellow man and turn the other cheek?
let's take $1.00 per person, $1.00 for material costs, and $1.00 for munitions and increase the cost x10% per year, indefinitely.
OUR cost has already eclipsed the entire value of the known world by 2,000 b.c.
So, without even needing to count exactly, nations need to find alternatives to wars. It is not so much that war is bad [even for war suppliers, war is bad if they are willing to consider the cost to everyone around them] but that wars are started for known reasons and these can be surmounted.
Wars are started for misunderstandings between neighboring villages, "states" and nations. or, each does understand the other's part but does not want to move from a economic or political position.
HE is a Jew, A Catholic, he demands more water, timber, iron, and, the reasons are endless in specific ways but in general, they are easily grouped.
Everyone wants to live but, unfortunately, some religious persons feel that some should live and others should not. Hmmm. Wonder what God says to them?
While the United Nations helps calm some angry nation's leaders and the UN also absurdly recognizes the "autonomous" rights of dictators as well as elected leaders, we still have national leaders who would rather ignore the history of the success of wars and would rather fight than seek partial compromises.
NOT one nation on earth ever "gets back" its "investment" [expenses] of wars. Can't be done because the direct costs are sometimes the lesser of all the costs.
The loss of a person who can contribute medicines and inventions and thus, save millions of lives in 'x' years hence does not get to directly enter this math and debate matrix, yet, it is because we lose these people, these innovators, that often, science and discovery is postponed dozens if not hundreds of years, at unfathomable costs, again!
Land, minerals, ports and other Things CAN BE bought. Funds are available.
Radical Muslims seeking to kill Christians makes no sense and radical Baptists seeking to eliminate radical Muslims seems logical but is not. The better approach is to demonstrate to radical everyone that religious moderation is the only way to save the earth.
IT is fantastically sad that some insane radical religious factions feel it is better to wipe the earth's slate clean and start over.
I wonder who they think will replace them if they were successful? Only more radicals who feel as they do?
And we know that when a dictator assassinates an elected leader, the dictator is soon wiped out anyway.
Inevitably, peace seekers win out. Dictators are eliminated. When more people can win, everyone wins.