The smart ones manufacture error coins that sell for thousands of dollars - there were many made in the 1970s that combined Australian/New Zealand/Fijian obvers

The smart ones manufacture error coins that sell for thousands of dollars - there were many made in the 1970s that combined Australian/New Zealand/Fijian obverses and reverses. Through the 2010s there has been another surge of such manufactured errors - generally one dollar coins made with 10c portraits (the 10c portrait is slightly smaller so it's a noticeable mistake).