nphx, you could call your police department or local hospital and ask them.
In my town one of the "women's clubs" has made that one of their fundraising causes and they provide the monitors. I think we also have a program where the police make daily calls to citizens to be sure everything's all right (the citizens sign up for this, obviously, as no one has called me yet
); maybe your area does too?
Of course once your mom has one of these she might be like my MIL and others who never used it because they didn't want to bother anyone even when she had fallen in the kitchen and lay on the floor for three hours trying to get herself up.