Im going over to the states soon and was thinking about purchasing afew silver bars while I was there. Would there be any problems bringing them back to Australia?
Shouldn't be any issues. Keep your receipts and print off a copy of this document (http://law.ato.gov.au/atolaw/view.htm?docid=GST/GSTR200310/NAT/ATO/00001) and keep it with you to show any Customs people.
