A DoD spokeperson said some time ago that they can only account for 30% of the weapons/equipment sent to Ukraine; wish I could remember if his statement also included $. From everything I read, much of everything is stolen.
Video of stinger at link:
https://t.me/s/intelslava/37389
A student in Bremen, Germany found an online store selling Stingers and contacted the police. Journalists from Hamburg and other cities have already found out that the weapons were intended for the Kharkov counteroffensive, but ended up on the European black market.