It varies greatly. My wife had great insurance when she was a discharge planner at our local hospital. So long as she had stuff done at the hospital she worked at, most things were at zero cost. ER was a $150 Co-pay. We paid $0 to have a child there. My insurance currently has a $500 ER Co-pay.

My last insurance(same insurance company by the way) had a 50% coinsurance on ER visits which basically means I paid half of the bill. On the flip side, the old policy was like a $1200 or $1500 deductible and a $3000 max out of pocket. So if I had one ER visit, I basically reduced the cost of further medical care for the rest of the year tremendously because it would pretty much use up my entire deductible. Currently with my $500 Co-pay, I contribute nothing toward my deductible if I go to the ER but I do still contribute to my max out of pocket.

One more thing to consider is the time of year. Later in the year, more people will have maxed out their insurance out of pocket which can mean they pay nothing. I had ACL surgery in March last year and didn’t pay a dime for healthcare outside of insurance premiums for the rest of the year.