Cheap bendable material for DIY project
Maybe something like sodium acrylate or polycarbonate (lexan) would work. Unlike acrylic sheets (plexiglass glass) the two I mentioned are less brittle and easier to fasten with screws and drilled holes. These materials can all be cut with a specialized handheld plastic cutter that looks like a razor.

The cost will depend on the thickness of material, but given that they're strong you could probably get away with bracing thinner sheets.