I can attest to private healthcare provision in the UK being hugely cheaper than the US - some of that can be attributed to emergency care and primary care (GP) being almost always covered by the NHS.
Here is a recent example of costs.
As a starting point for this article, we wanted to find out prices for a ‘typical’ buyer - we got quotes for a 33 year old, living near Oxford*, from the four largest UK Health Insurers –BUPA, AXA, Aviva and Vitality. This gave us prices between £26 and £48 per month or £312 and £576 per year.