As I said I cant remember the figures but the benchmark was living at home and doing an intensive PPL some 30 miles away in winter in England, the expenses then would be travel and most probably a time penalty due to weather. The USA calculation was everything expended from the first hour in England, exams, TSA, cost of US course, flights, expenses over there and flying on return. It was not scientific or audited.
However, the main point is this. While waiting for TSA clearance and tossing about with fingerprints (do this in advance) and visiting the US embassy, get the ground school done and at least cover the basics up to and just before the circuit in the same type of aeroplane you will be training on. He told me it was invaluable as he was the student going out for a meal or resting while others had their heads stuck in books and were sitting in classrooms instead of flying or having quality briefs/de-briefs.
Not a lot in it when you add it all up but the US route gives you a bit of a holiday and experience in another country but with all the attendant hassle of the visa requirements.