Cheap Precision Cut Aluminium
Professional laser cutters like to charge ridiculous amounts of money to get material cut.
Coincidentally, thin precision cut aluminium is also a requirement for screen printing solder paste on to boards using stencils. From a supplier such as PCBWay you can order them with or without frame. For example a framed aluminium stencil is about US$150 for a 400x400mm.
Without the frame it is approximately US$40, much cheaper than getting it laser cut professionally.