Strike gold with your loose change: the most valuable Australian rare coins

It comes as prices for some $2 coins have reached $280.

Rare coins including Australia's half penny from 1923 or Adelaide pound from 1852 were worth thousands of dollars, if not hundreds of thousands, but more humble and common finds could net a respectable sum.

Coin enthusiast Joel Kandiah said the secret to finding a valuable coin was high popularity among collectors as well as having limited production or "low mintage".

"Broadly speaking, low mintage coins will see high demand because they're harder to find," Mr Kandiah said.

But it's not always the case, he said.

"A 1972 five cent coin has historically been a popular coin due to low mintage but is not a popular coin in the market overall. Low mintage coins aren't automatically considered 'rare'", he said.

Coloured two dollar coins, with low mintage and high demand, were fetching large sums from collectors on eBay.

A 2012 coloured red poppy $2 coin, in mint condition, could sell for $280 because only half a million coins were produced using that design, Mr Kandiah said.

"The 2013 coronation two dollar coin has a low mintage of 994,000, that coin can be worth anywhere between $40 and $140 depending on condition," he said.

"Australian coin collecting is more than just coloured $2 coins as there are some incredible gems to be found in your change. Whilst they are rare, they are definitely not impossible to find".

A $1 coin minted in 2000 could fetch collectors between $300 and $4,000, based on its condition, if the Queen's portrait has a thicker outlining border than the opposite side.

An accidental run of $1 coins were minted using a 10 cent obverse, or heads, die in 2000 leading to the wildly popular collectible mistake.

Millennium 50 cent coins, also minted in 2000, with an arching Australian flag under the words "millennium year" could be worth between $50 and $1,000 if the flag design is recessed instead of raised.

Some 20 cent coins, minted in 1966, included a rare fault. The baseline of the 2 on the tails side was "wavy" and this coin could be worth between $200 and $3,500 based on its condition.

Read more: Minted: the 5 cent coin that's worth a fortune

Older generations may remember coins clinking in their pockets and collecting dust in their car's cup holders but tangible currency has become increasingly uncommon in Australia.

Mr Kandiah, a high school teacher in Canberra, said his students perceived coins as curiosities from another era and had often only interacted with their parents' change.

"I'm a millennial and I'll use cash at the supermarket but I mainly use card," he said.

"And compare that to my parents who use cash as much as they can.

"The intergenerational differences in cash usage are quite stark."

"The way [Generation Z and Alpha] see the tangibility of money is very different to how I see it or how my parents see it," Mr Kandiah said.

Payment method matters. Willingness to spend is higher when people pay with debit cards compared to cash, research from the Copenhagen Business School found in 2015.

Mr Kandiah has noticed many people from the younger generation appreciate coin collecting as a hobby and he advises them to be clear-minded about what they were aiming to collect.

A collector trying to find "one of everything" would struggle due to the volume of distinct coins minted in Australia, he said.

He advised new collectors to focus on "what they loved about coins", from cricket memorabilia to Australia's Big Things, and find a small selection of coins at an affordable price.