If you are filming in México, you are probably buying materials and supplies in California that are being shipped into México. Many assume that this situation exempts them from having to pay U.S. sales tax on those materials. According to the California State Board of Equalization, you are NOT entitled to a sales tax exemption if you take possession of materials in the U.S. unless:
1. Orders are shipped to you c/o your exporter at the border with a forward through address to México.
2. You have a Bill of Lading indicating a Mexican delivery address. But bills of lading can only be issued by common carriers.
Transportation Department trucks and drivers do not qualify as common carriers. Vendors may ask for copies of shipping documents to confirm that the goods you’re buying are being sent directly to México. But according to the Board of Equalization, copies of pro-forma shipping invoices and pedimentos alone would not qualify you for a sales tax exemption.