Common cost-effective fill materials include:

1. Local Stones or Rocks: Using stones or rocks sourced nearby can significantly reduce transportation costs. These should be durable and suitably sized to prevent falling through the mesh.

2. Recycled Materials: Broken concrete, bricks, or rubble from construction demolition can be an economical fill if allowed by project specifications.

3. Natural River Gravel: If available nearby, river gravel can be inexpensive and effective as gabion fill.

4. Fieldstones: Stones collected from fields or agricultural land can be used if they are stable and durable.