[scrape] (the bottom of|) the barrel

to have no option but to make use of people or things of very poor quality

The origin of the idiom "scrape the barrel" can be traced back to the literal act of scraping the bottom of a barrel. In earlier times, barrels were commonly used for storage, and when the contents of the barrel were almost depleted, one would scrape the remaining bits from the bottom. This action was often associated with collecting leftovers or obtaining the last remnants of something.

The company was desperate to hire new employees and had to scrape the barrel, resorting to candidates with minimal qualifications and experience.
With the pantry nearly empty, the family had to scrape the barrel for dinner, making a meal out of the few ingredients left in the kitchen.
The teacher had exhausted all available resources and had to scrape the the bottom of barrel to find additional teaching materials for the students.
The film production faced budget constraints and had to scrape the barrel for costume options, resulting in subpar outfits for the actors.
The coach had to scrape the the bottom of barrel for substitutes after multiple injuries, putting inexperienced players on the field for the crucial game.