Amazon has the First Alert Car Fire Extinguisher (AUTO5) for $15 with free shipping on $25+ or with Prime. List price: $28. Features metal pull pin with safety seal, mounting bracket and strap, 5-B: C rated for vehicles.
Amazon has the Bosch HEPA Premium Cabin Air Filter (6047C) for $14 with free shipping on $25+ or with Prime. Features melt-blown electrostatic layer, cabin air filters should be replaced at least once every 12 months (or every 12K miles).