The ex-England defender is adamant that the potential rewards on the United table far outweigh the financial risks.
Anderson, 56, told the Daily Star: "I know it's a lot of money, that he is 29 and you're not going to get a lot of money back for him in a few years' time - but it's about now.
"It's about next season and the one after that and if we can win the league back, get a good run in Europe and the Champions League, then it is money well spent.
"The manager is thinking short-term at this moment. He's not thinking about the next five or six years. He wants that title back and he wants it now.
"He has set his stall out and if Van Persie is the catalyst for winning the Premier League, which I think he will be, then you do the deal all day long.
"That's why I'm not bothered about the fee. RVP is a great signing. He's played in the Premier League for years, he fills so many roles and scores goals wherever he plays.
"If he's scoring 30 goals a season and Wayne Rooney's scoring goals too, then everyone is going to sit up and take notice of United. That is some serious firepower."