I don't believe the US spends any money on the UK. The US does spend around 0.18% of their GDP on foreign aid, which has always been considered a good thing. The US helps a lot of nations around the planet which in turn buy and support America. I agree with looking inwards before outwards, however economies are global in the 21st century, every major corporation operates globally, and America is a leader in that field. The US have extended their capitalist beginnings into a global competitive market, which in turn benefits Americans first and foremost.
Anyway I'm not getting into a political debate as a foreigner, I am merely speaking as an individual. Just because I am from the UK does in no way mean I represent nor align myself with the UK government. We're all citizens of this planet first and foremost, my government does not speak for me so I was only showing support.