To answer your question it varies wildly based on where you get your insurance. It could cost anywhere between fairly reasonable (government insurance) or 4 limbs and a first born depending on your employer. The "free" healthcare we now have is more expensive then what anybody I know who is covered through an employer pays.
The truths of our system are
A. You don't know what its going to cost
B. But its going to be a lot
C. Most employers are in an eternal struggle to keep costs low while trying to get decent benefits for their employees.
For most of us, some if not many aspects of our coverage, will change on an annual basis which then starts the cycle again.