While there is a slew of professionals athletes who have ventured into cryptocurrency from Tom Brady to Saquon Barkley in recent months, NBA legend Charles Barkley isn't biting.

"My people do not believe in crypto," Barkley tells CNBC Make It. "I got a couple of financial guys. One of them said, 'If I ever put you in crypto, you should fire me on the spot.'"

"And listen, I know that [crypto] is all over the place, to be honest with you, but my people don't believe in [it]," he says.

Though Barkley did not elaborate on why his advisors are against crypto, many experts warn cryptocurrencies are volatile and recommend that people only invest money they can afford to lose. For example, since mid-April, bitcoin, the largest cryptocurrency by market cap, went from a high of around $63,000 to around $39,000 as of Monday morning, according to Coindesk.

Still, many athletes and investors are bullish on the future of digital currencies.

In May, seven-time Super Bowl champion Tom Brady told Coindesk that he is "a big believer" in crypto but would not disclose specific details about which crypto assets he's invested in. While New York Giants star Saquon Barkley announced plans to convert all of his income from marketing deals and endorsements to bitcoin.

Charles Barkley, 58, who earned more than $40 million in salary over the course of his 13-year NBA career also says the biggest money lesson he's had over the years is, "learn to say, no."

"And don't feel bad about it," he says.

The Alabama native says when you become famous and start making money, "people ask you for money every single day of your life. Every day."

So it's imperative to say, "no," even when it's to family and friends.

If you don't, you will end up going broke and it will ruin all of your relationships, Barkley told American Century Investments in 2016. Barkley ran into some trouble in 2019 after losing millions to his longtime friend and business associate, Donald Watkins, in an investment scam.

As for an investment tip, Barkley, who has guest-starred on ABC's "Shark Tank" and invested in start-ups like Zorpads and SubSafe, says shoot for just "singles and doubles."

"If you get lucky and hit a triple or a home run, that's fine. But you really just trying to hit singles and doubles."

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Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank."