This has never been a secret. The only people that think we are giving Ukraine piles of cash are just repeating what isolationist politicians say.
The United States feeds its own stockpiles first and pushes out older munitions where they need to be used. Even air to air or air to ground missiles have a super-short lifespan. It's probably cheaper to send old missiles to Ukraine than fully service ones that are reaching the end of their service life.
The raw cash for almost every conflict we support goes directly to our military industrial complex. Like I said at the very start: It's not a secret.