Not super low. It starts to make sense around 1000 units. I’ve gotten runs of 2500 done domestically. But it is pretty hard to find domestic injection molders for consumer work - they will give you an FU quote at best because they cater to high volumes and industrial customers.

And they’ll make the molds in China anyway. Chinese molders are hungry — they will work with low volumes and offer a bunch of integrated services. But if you don’t know what you’re doing you will end up with bad parts over schedule.

Easiest way to get started is to use ProtoLabs. They charge lower prices on molds in exchange for higher part cost, are way faster than China, and have way better customer service.