Fortunately most ERs will let you make installment payments... at least until they send the account to a bill collector.
If one has insurance, make the facility run the billing through the insurance carrier FIRST. This will ensure the amount paid is the true patient responsible amount. Medical providers are horrible about returning amounts paid by patients not owed after insurance pays. Just a little tip.
It’s free if you are an illegal alien.
There's a dirty little secret here. The bill collectors can harass you, but they're not allowed to ding your credit if you are late on health care bills.