Only In Australia

Lobster, pineapple, gray nurse
Australians don't barter with lobsters and pineapples, but most have had at least one friend ring them up (or hit them up at the pub) to lend a lobster or a pineapple.
The $20 note being a sparkling red (lobster) and the $50 note being bright yellow (pineapple) lends itself to the phrase. The $100 note, a blue gray, has now been named after a shark (grey nurse). The less important $5 and $10 notes are often referred to as past international sporting stars -- Pam Shriver (fiver) and Ayrton Senna (tenner).