Charging by polygons is such a weird, arbitrary thing to do. I'd be able to make a decent 6k character much faster than a decent 2k character, for example.
This is according to a famous artist I took part in his workshop. He said he usually bill clients in $$$/day. So that leaves some room to wiggle and add more when clients want fixes or changes. To a lesser extend he'd charge per-item too and that way he'd get paid equally whether he spent 2 days or 3 weeks to finish that…
its what you decide to set it at. take into account, how long the job goes for, how hard you'll have to work (will you be working 24/7 or 9/5? how experienced you are and what you lose by not taking the job (being unavailable for other work) or what you might gain (working with a top notch team of experts to help you raise…