Back in 1990/91 a coalition of 28 countries defeated the Iraqi military and drove it out of occupied Kuwait with roughly 2/3 U.S. troops. It seemed like a post-Cold War triumph for peace among nations at the time.
Some countries did not participate much or not at all with military means, but provided subsidies to support in particular the U.S. effort fiscally.
The U.S. Department of Defense has estimated the cost of the Gulf War at $61 billion.Kuwait, Saudi Arabia and other Gulf states covered $36 billion.Germany and Japan covered $16 billion.
In hindsight, I think this was the biggest German foreign policy sin in many decades. Even the decision to de facto go to war against Yugoslavia in 1999 pales because without this earlier sin, it would likely not have happened.
To make a "won" war almost for free gave a terrible, utterly misleading signal to the people in the United States; a signal that war may be profitable. No doubt all that glory with a neat parade in best weather through flag-decorated streets, the testing of military equipment, the prestige gain et cetera was worth a very few billion dollars and about a hundred dead war heroes?
The U.S. had regained its appetite for great power games post-Vietnam already under Reagan and Bush sr before the 1990/91 Gulf War, but afterwards it was altogether different, public approval was much easier to get and sought after instead of rather sudden and previously unannounced military action. "Cruise missile diplomacy", the casual bombing of other countries, was born soon after 1991. Iraq had met all disarmament requirements by 1996, but wasn't left alone at all, and eventually broken for good in 2003.
What seemed like a moment of triumph for a world in which invading other countries was unacceptable and to be punished by the international community turned into the moment when one country decided that bombing and invading other countries does cost little, is fun and perfectly fine as long as it's the only country that does it. The German government helped to create that impression, with German public funds, fed by German taxpayers.