1. shift/fend for oneself
to get along by oneself; to support oneself.
Ex: I'm sorry, I can't pay your rent anymore. You'll just have to shift for yourself.
When I became twenty years old, I left home and began to fend for myself.
2. Paddle one's own canoe
to do something by oneself; to be alone.
Ex: I've been left to paddle my own canoe too many times.
Sally isn't with us. She's off paddling her own canoe.
3. Keep the wolf from the door
to maintain oneself at a minimal level
Ex: We have a small amount of money saved, hardly enough to keep the wolf from the door.