Where do your teams purchase your polycarbonate?

[protoserge]

You can look into Duraplex. It is an inexpensive impact-resistant acrylic alternative to Lexan/polycarbonate. It is available at Lowe's in 24"x48"x0.080" sheets for about $26.

I don't know what your roller arm design would look like or its requirements, but if it was an over-the-bumper style, I would assume you'd need a lot of torsional rigidity and strength for robot and field element impacts. There are different ways to achieve rigidity and strength, one of which could be the selection of a different support material such as plywood or sheet metal.