throw good money after bad

-potrošiti dodatni novac nakon što smo nešto već platili; trošiti novac na nešto što neće nikada uspjeti

I bought a used car and then had to spend $300 on repairs. That was throwing good money after bad.
The Browns are always throwing good money after bad. They bought an acre of land that turned out to be swamp, and then had to pay to have it filled in.
Investors in the project began to pull out as they realised they were simply throwing good money after bad.