The USA has already provided over $750 million worth of military aid to the Ukraine and now it is sending them Javelin missiles which cost $78,000 per missile. All paid for by the American tax payers.
The US government currently spends about $600 billion per year on the Department of Defense, part of that funding is given away as free military aid/weapons to other countries. The only winners in the game of war are the corporations who create these weapons of war and they are paid by the US government with your tax dollars.
More info in the article;
http://nationalinterest.org/blog/the-buzz/americas-javelin-missiles-are-going-ukraine-can-they-stop-23858