I'm heading back from Japan today, and my family got a bunch of checkups and medical stuff done while we were here.
Even without insurance all our procedures cost total less than ~$100 apiece.
The most expensive thing I've ever had in japan was my full body workup last year for $500.
It included: stomach ultrasound, 5 blood tests, eye exam, MRI(brain) and barium scan. All without insurance.
By comparison, in the US I was charged $1200 to get my daughters arm cast changed (no xray, just a nurse changing the cast), and $800 for an ultrasound.
It is literally cheaper to fly to Japan and get treatment without insurance than to use my health insurance that I pay $1300/month for.
Also, as a bonus, because of the set prices of medical procedures in Japan, insurance is super cheap. For a family of 4 it was costing me around $500/month when I used to live here.