Like most young boys, Josh Mangleson grew up accumulating a decent collection of Lego.
Little did he know his favourite little plastic bricks would one day help him own some real ones.
"Most people still don't believe it when I tell them I put a deposit on our home with Lego!" the 25-year-old told news.com.au.
When he began collecting Lego as a child, Mr Mangleson didn't know little toys could be such big business. But once he began shopping for new sets online, a teenage Josh realised his old Lego was worth a pretty penny — especially in the condition he kept it.
"In high school before I had my first job I'd try and find ways of making money to buy new Lego sets. I'd look at buying them online, and I started to see the values on some of my older sets and could hardly believe my eyes. So I started to see my own Lego collection as a bit of an investment.
"I was always a bit of a completionist, so every set had to be kept together with all of its original parts, instruction manual and even the boxes. As a result I amassed quite a sizeable personal Lego collection over the years (particularly in the Star Wars theme)."
But it wasn't until Mr Mangleson started university that it hit him: He was sitting on a goldmine.
"I didn't step into investing until 2016 when I entered into my first year of university doing a Bachelor of Property Economics. We covered various types of investment and it got me quite motivated to do it," he admits.
The driven teenager started using an online tool to collate his collection through a website called Brickpicker, where he fell hard and fast for the art of Lego investment.
Around mid-2016, Mr Mangleson went all in. "I went on a buying frenzy over 12 months," he said.
"I think my parents thought I was crazy when I started spending thousands of dollars at a time on Lego and came home with car boots full of sets. But when I started showing them I was turning a profit they soon became supportive of it."
Before liquidating his entire savings into Lego sets, Mr Mangleson had a well-planned rationale for purchasing.
"First, making sure to buy sets at deep discount," he explained.
"Second, near the end of their shelf life — often around two years for Lego, but this varies. And finally, understanding what's going to be popular and what people haven't been able to get their hands on. Knowing your market is key, and my years of collecting definitely helped."
The quickest profit he managed to turn over happened in just seven days.
"I picked up a set of Simpsons Series 1 Minifigures from Cash Converters for less than $50. I sold them a week later for $150."
Further proof the Lego market is seriously booming in Australia comes straight from one of the country's biggest online shopping retailers: eBay. The bargaining platform revealed to news.com.au Lego sets were selling every second on the site just last month, attributing the 89 per cent increase to the debut of Nine's reality show Lego Masters.
"Some individual parts and minifigures are incredibly rare," Mr Mangleson explained. "I sold a single radar dish (piece) for $120, and I had a couple of minifigures which I sold individually for over $500 each."
In the last 12 months alone, more than 400,000 Lego sets have been bought on eBay, equalling about $21 million in sales. And a chunk of those 400,000 sets belonged to Mr Mangleson.
After holding onto each set for approximately 18 months, Mr Mangleson "saw an average return of over 40 per cent (which equated to an average of 25 per cent above RRP)".
He estimates selling around 75 per cent of the sets in 2018, taking full advantage of free or $1 eBay listings and other free online marketplaces. These included Gumtree and Facebook — especially Facebook groups dedicated to Lego within Australia.
"I sold around 120 investment sets, and around as many I personally owned — around 250 sets all up," Mr Mangleson guessed. "On top of my investing, I sold almost my entire personal Lego collection which was also at a significant profit. Though I never kept track of purchase costs for these, I'd estimate I quite easily doubled my money on them."
All up, he scraped together just over $20,000 selling the sets.
This, combined with the Queensland First Home Owners' Grant of $15,000, allowed Mr Mangleson and his wife Jess to do what most Millennials can't these days: buy their own home.
"Thankfully, my now-wife has always been very trusting of my ability to manage my finances, so she was happy to go along for the ride," Mr Mangleson laughed.
"Although when my savings account hit zero and it was sitting in plastic bricks, I'm sure there was a moment or two of worry in there!"
Luckily, Mr Mangleson was able to hold onto his most prized possessions in the process: "A 75192 Millennium Falcon and a 10188 Death Star," he says. The Falcon alone can be sold for up to $1700 (depending on its condition).
"Don't expect to see them for sale anytime soon."