However, Mr Musk said the site would always be free for “casual users”. He had previously said he wanted to “make Twitter better than ever by enhancing the product with new features”.
The SpaceX founder tweeted: “Ultimately, the downfall of the Freemasons was giving away their stonecutting services for nothing.
“Twitter will always be free for casual users, but maybe a slight cost for commercial/government users.”
Meanwhile, the multi-billionaire has reportedly told potential investors that he may return the social media firm to the stock market in just a few years.
Mr Musk reportedly plans to sell Twitter shares again in as little as three years after buying it, according to the Wall Street Journal, which cited people familiar with the matter.
His takeover of the company is expected to be completed later this year, subject to conditions including the approval of Twitter’s shareholders and regulators.
Under the deal he will buy all the shares in the company that are currently available on the stock market, taking it from being a publicly-owned company to a private one.
Earlier, Mr Musk had tweeted a link to a CNN story which called for some of the US’ biggest brands to boycott Twitter if Mr Musk rolls back content moderation policies limiting hate speech.
He has argued that Twitter’s moderation policies pose a threat to freedom of speech.
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Mr Musk is the world’s richest person, with an estimated net worth of around $250bn, mostly due to his Tesla stake.
He also has a controlling stake in the rocket company SpaceX, which is estimated to be worth $100bn.
Last week, Mr Musk sold roughly $8.5bn worth of shares in Tesla, which led to speculation that he will use the money to help finance his buyout of Twitter.