The slang or colloquial term tinnie or tinny has a variety of meanings, generally derived from some association with the metal tin, or aluminium foil which has a loose allusion to tin.
"Tinnie" is the common term for a commemorative medal made from a non-precious metal such as zinc or tin (or even plastic) and with provisions for being attached to a garment and displayed while worn. Such medals were commonly sold or given away at public events to build group cohesiveness or to lend prestige to the wearer. The "golden age of the tinnie" was World War Two, and the Nazi Party and the USSR were among the most prolific disbursers of them. They are avidly collected today by hobbyists and, although usually inexpensive to obtain, are often collected in conjunction with coins, exonumia, military awards and decorations and other related small stamped or cast metal objects.
In New Zealand, a "tinny" or "tinnie" can be a small package of cannabis wrapped in tin foil (cf. 'foilies' in Australia), retailing for between NZ$20–25 (depending on the region). A building where such retailing takes place (commonly a superficially unremarkable home) is a "tinnie house". Other drugs such as methamphetamine may be available as well. In recent years the term has become not unusual in New Zealand court judgments involving the Misuse of Drugs Act.
Another variant of "tinny"/"tinnie" is as a slang term for a can of beer, commonly used in Australia, New Zealand and some parts of the UK. Most items referred to in this region as "tinnies" are actually now made of aluminium.