"De levde fra hånd til munn."
Translation:They lived from hand to mouth.
it means to be so poor that you can only afford food and perhaps some other basics, but nothing else
Perhaps even more literally - you are living so close to the edge that you consume everything you can get your hands on - there's nothing in the pantry, nothing to set aside - as soon as you get it, you use (eat) it.
I've heard it a good number of times. I've lived all over the USA and don't think it is regional here. Not an everyday expression, perhaps, but one you hear once in a while.