(from) hand to mouth
With just the bare minimum of money, food, or resources to survive, with little or nothing else to spare. Usually preceded by "live." It's been pretty hand to mouth these days. If I don't find work soon, I don't know how we'll get by. With another child on the way, it looks like we'll be living from hand to mouth for the foreseeable future.
(from) hand to mouth
satisfying only your immediate needs because of lack of money for future plans and investments. 1960 Lynne Reid Banks The L-Shaped Room I'm twenty-eight years old and I'm still living from hand to mouth like a bloody tramp.