You shouldn't even need to call around, prices for routine procedures like checking for strep should be clearly posted. The bill shouldn't change if you're insured or uninsured, just the payer changes.

There's obviously some variation here, and for that an hourly rate makes sense.

Health care should be more like car repair: go in for a quote, then pay when you decide on a provider. Obviously emergencies are different, but things like strep or broken bones are pretty common, so they should have a set price.