I'm fairly new but hopefully i can help. I have recently worked on the cars from the movies as well. Grilles were resin (modelhaus) but hacked up pretty good. The mesh, if looking for budget materials, check local dollar store for a pan strainer. Could get 30 grilles easy, and only a dollar. These are the only pics I have handy right now and weren't finished at that time...
Don't forget competition, as that also determines price, In this case since there is no competition, they can make the price whatever they want! Now if there was 2-3 companies offering it, the competitions would drive the price down..