"My earliest memories are re-packaging baseball cards and selling them," Cuban says on ABC's "Shark Tank," where he is an investor.
Now worth $3.3 billion according to Forbes, Cuban has an idea for a money making scheme to spare.
It's a business that almost anyone can set up, according to a tweet by Cuban Thursday.
"[In my honest opinion] the easiest money right now for anyone 14 or older is digging in to be an expert in Amazon Alexa and Google Home, and every compatible device." Cuban tweeted.
"Then, I would offer to consult and configure the apartment and homes of everyone I know, and everyone they know."
Young entrepreneurs would be wise to get started now — Amazon announced in December that the company sold "tens of millions" of devices powered by its smart voice assistant, Alexa, over the holidays. Google too, announced in January it sold "more than one Google Home device every second since Google Home Mini started shipping in October."
Cuban says an early key to his own success was his ability to educate himself on technology. In his 20s, Cuban got a job selling software at a store in Dallas called Your Business Software and hustled to learn as much as he could.
"Every night I would take home a different software manual, and I would read them," he writes on his blog. "Every night I would read some after getting home, no matter how late."
For Cuban, who later built and sold two technology businesses, it paid off.
He writes, "A guy with little computer background could compete with far more experienced guys just because I put in the time to learn all I could."
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Disclaimer: CNBC owns the exclusive off-network cable rights to "Shark Tank."
This story has been corrected to reflect the day of Cuban's tweet.