Desktop Vacuum Former: manufacture your own plastic that is heated and shaped to a formed mold. Plastic used can be recycled 2L bottles, foam sheets, PETG, acrylic. To use, place mold on perforated board. Secure plastic to insert. Heat. Vacuum. Plastic will form around mold. Remove plastic and trim to fit.
Requires vacuum, heatgun, machine screws and nuts, aluminum foil, and glue.
Object material designed for: P2 MDF or wood .25 thickness; 3 files; assembly instructions: http://support.ponoko.com/entries/20509538-desktop-vacuum-former
Save money and delete the holes on the perforated board to drill yourself.