This context comes from the movie "Gangs Of New York" The phrase occurs when one of the characters is describing the types of gangs and people living in New York.
"Hellcat Maggie tried to open up her own grog shop. But she drank up all her own liquor and got thrown out on the street. Now she's on the lay for everything."
The only thing I found is the phrase:
"lay for"
To be waiting to attack someone: Muggers were laying for the unsuspecting pedestrian in the dark alley.
This is a phrasal verb but the sentence in question seems like a noun phrase