You are correct, rates vary by region and by experience.
There is one rate that would include your equipment.
There is an other rate when you free-lance at another post house.
$100/day is way to low for either scenario.
I would just guess that a newbe editor free-lancing at a post house could charge $25-$40 an hour.
Maybe $50/hour on your own system.
But it’s all subjective and market demands or lack there of are factors.
Chris